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Sample records for quinolone-resistant escherichia coli

  1. Introduction of quinolone resistant Escherichia coli to Swedish broiler population by imported breeding animals.

    Science.gov (United States)

    Börjesson, Stefan; Guillard, Thomas; Landén, Annica; Bengtsson, Björn; Nilsson, Oskar

    2016-10-15

    During recent years a rapid increase of quinolone resistant Escherichia coli have been noted in the Swedish broiler population, despite the lack of a known selective pressure. The current study wanted to investigate if imported breeding birds could be a source for the quinolone resistant E. coli. The occurrence of quinolone resistant E. coli was investigated, using selective cultivation with nalidixic acid, in grand-parent birds on arrival to Sweden and their progeny. In addition, sampling in hatcheries and empty cleaned poultry houses was performed. Clonality of isolates was investigated using a 10-loci multiple-locus variable number tandem repeat analysis (MLVA). To identify the genetic basis for the resistance isolates were also analysed for occurrence of plasmid-mediated quinolone resistance (PMQR) determinants and characterization of chromosomal mutations. E. coli resistant to nalidixic acid occurred in grandparent birds imported to Sweden for breeding purposes. Four predominant MLVA types were identified in isolates from grandparent birds, parent birds and broilers. However, resistant E. coli with identical MLVA patterns were also present in hatcheries and poultry houses suggesting that the environment plays a role in the occurrence. Nalidixic acid resistance was due to a mutation in the gyrA gene and no PMQR could be identified. The occurrence of identical clones in all levels of the production pyramid points to that quinolone resistant E. coli can be introduced through imported breeding birds and spread by vertical transmission to all levels of the broiler production pyramid.

  2. Plasmid-Mediated Quinolone Resistance (PMQR) Genes and Class 1 Integrons in Quinolone-Resistant Marine Bacteria and Clinical Isolates of Escherichia coli from an Aquacultural Area.

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    Tomova, Alexandra; Ivanova, Larisa; Buschmann, Alejandro H; Godfrey, Henry P; Cabello, Felipe C

    2017-06-23

    Antimicrobial usage in aquaculture selects for antimicrobial-resistant microorganisms in the marine environment. The relevance of this selection to terrestrial animal and human health is unclear. Quinolone-resistance genes qnrA, qnrB, and qnrS were chromosomally located in four randomly chosen quinolone-resistant marine bacteria isolated from an aquacultural area with heavy quinolone usage. In quinolone-resistant uropathogenic clinical isolates of Escherichia coli from a coastal area bordering the same aquacultural region, qnrA was chromosomally located in two E. coli isolates, while qnrB and qnrS were located in small molecular weight plasmids in two other E. coli isolates. Three quinolone-resistant marine bacteria and three quinolone-resistant E. coli contained class 1 integrons but without physical association with PMQR genes. In both marine bacteria and uropathogenic E. coli, class 1 integrons had similar co-linear structures, identical gene cassettes, and similarities in their flanking regions. In a Marinobacter sp. marine isolate and in one E. coli clinical isolate, sequences immediately upstream of the qnrS gene were homologous to comparable sequences of numerous plasmid-located qnrS genes while downstream sequences were different. The observed commonality of quinolone resistance genes and integrons suggests that aquacultural use of antimicrobials might facilitate horizontal gene transfer between bacteria in diverse ecological locations.

  3. Prevalence of quinolone resistance mechanisms and associations to minimum inhibitory concentrations in quinolone-resistant Escherichia coli isolated from humans and swine in Denmark

    DEFF Research Database (Denmark)

    Cavaco, Lina; Frimodt-Møller, Niels; Hasman, Henrik;

    2008-01-01

    Prevalence of quinolone resistance mechanisms and associations to minimum inhibitory concentrations (MICs) of nalidixic acid (NAL) and ciprofloxacin (CIP) were investigated in 124 Escherichia coli isolated from humans (n = 85) and swine (n = 39) in Denmark. The collection included 59 high-level CIP......-resistant isolates (MIC >= 4) from human (n = 51) and pig origin (n = 8) and 65 low-level CIP-resistant isolates (MIC >= 0.125) from human (n = 34) and pig origin (n = 31). Resistance by target modification was screened by PCR amplification and sequencing, of the quinolone resistance determining regions (QRDRs......A and qnrS genes conferring quinolone resistance by target protection were detected in two human low-level CIP-resistant isolates that did not display NAL resistance. As expected, target mutation in QRDRs was the most prevalent mechanism of quinolone resistance. This mechanism was complemented by efflux...

  4. Dynamics of Quinolone Resistance in Fecal Escherichia coli of Finishing Pigs after Ciprofloxacin Administration

    OpenAIRE

    Huang, Kang; Xu, Chang-Wen; Zeng, Bo; XIA, Qing-Qing; Zhang, An-Yun; LEI, Chang-Wei; Guan, Zhong-Bin; Cheng, Han; Wang, Hong-ning

    2014-01-01

    ABSTRACT Escherichia coli resistance to quinolones has now become a serious issue in large-scale pig farms of China. It is necessary to study the dynamics of quinolone resistance in fecal Escherichia coli of pigs after antimicrobial administration. Here, we present the hypothesis that the emergence of resistance in pigs requires drug accumulation for 7 days or more. To test this hypothesis, 26 pigs (90 days old, about 30 kg) not fed any antimicrobial after weaning were selected and divided in...

  5. Prevalence and characteristics of quinolone resistance in Escherichia coli in veal calves.

    Science.gov (United States)

    Hordijk, Joost; Veldman, Kees; Dierikx, Cindy; van Essen-Zandbergen, Alieda; Wagenaar, Jaap A; Mevius, Dik

    2012-04-23

    Quinolone resistance is studied and reported increasingly in isolates from humans, food-producing animals and companion animals. Resistance can be caused by chromosomal mutations in topoisomerase genes, plasmid-mediated resistance genes, and active transport through efflux pumps. Cross sectional data on quinolone resistance mechanisms in non-pathogenic bacteria from healthy veal calves is limited. The purpose of this study was to determine the prevalence and characteristics of quinolone resistance mechanisms in Escherichia coli isolates from veal calves, after more than 20 years of quinolone usage in veal calves. MIC values were determined for all isolates collected as part of a national surveillance program on antimicrobial resistance in commensal bacteria in food-producing animals in The Netherlands. From the strains collected from veal calves in 2007 (n=175) all isolates with ciprofloxacin MIC ≥ 0.125 mg/L (n=25) were selected for this study, and screened for the presence of known quinolone resistance determinants. In this selection only chromosomal mutations in the topoisomerase type II and IV genes were detected. The number of mutations found per isolate correlated with an increasing ciprofloxacin MIC. No plasmid-mediated quinolone resistance genes were found. The contribution of efflux pumps varied from no contribution to a 16-fold increase in susceptibility. No correlation was found with the presence of resistance genes of other antimicrobial classes, even though all quinolone non-wild type isolates were resistant to 3 or more classes of antibiotics other than quinolones. Over twenty years of quinolone usage in veal calves in The Netherlands did not result in a widespread occurrence of plasmid-mediated quinolone resistance, limiting the transmission of quinolone resistance to clonal distribution.

  6. Quinolone-resistant Escherichia coli in Poultry Farming.

    Science.gov (United States)

    Hricová, Kristýna; Röderová, Magdaléna; Pudová, Vendula; Hanulík, Vojtěch; Halová, Dana; Julínková, Pavla; Dolejská, Monika; Papoušek, Ivo; Bardoň, Jan

    2017-06-01

    Increasing bacterial resistance to quinolone antibiotics is apparent in both humans and animals. For humans, a potential source of resistant bacteria may be animals or their products entering the human food chain, for example poultry. Between July 2013 and September 2014, samples were collected and analyzed in the Moravian regions of the Czech Republic to isolate the bacterium Escherichia coli. As a result, 212 E. coli isolates were obtained comprising 126 environmental isolates from poultry houses and 86 isolates from cloacal swabs from market-weight turkeys. Subsequently, the E. coli isolates were tested for susceptibility to selected antibiotics. Resistance of the poultry isolates to quinolones ranged from 53% to 73%. Additionally, the presence of plasmid-mediated resistance genes was studied. The genes were confirmed in 58% of the tested strains. The data on resistance of isolates from poultry were compared with results of resistance tests in human isolates obtained in the same regions. The high levels of resistance determined by both phenotyping and genotyping methods and reported in the present study confirm the fact that the use of fluoroquinolones in poultry should be closely monitored. Copyright© by the National Institute of Public Health, Prague 2017.

  7. Genotypic characterization of quinolone resistant-Escherichia coli isolates from retail food in Morocco.

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    Nayme, Kaotar; Barguigua, Abouddihaj; Bouchrif, Brahim; Karraouan, Bouchra; El Otmani, Fatima; Elmdaghri, Naima; Zerouali, Khalid; Timinouni, Mohammed

    2017-02-01

    This study was conducted to assess the retail food as a possible vehicle for antimicrobial resistant, particularly quinolones resistant and pathogenic Escherichia coli. We determined the prevalence and characteristics of nalidixic acid (Nal) resistant E. coli isolates from diverse retail food samples. In all, 70 (28%) of 250 E. coli isolates studied were Nal-resistant E. coli and 91% of these were multi-drug resistant. Plasmid mediated quinolone resistance genes were identified in 32 isolates, including aac(6')-Ib-cr (n = 16), qnrS1 (n = 11) and qnrB19 (n = 7). Mutations in gyr A and par C genes were detected among 80% of the isolates, and the isolates showed substitution Ser83-Leu and Asp87-Asn in gyrA and Ser80-Ile in parC. In addition, three different gene cassettes were identified (aadA1, aadA7, aac(3)-Id) in 18%. Virulence-associated genes stx1, eae, sfa, hlyA and stx2 were found in six (8%), three (4%), two (3%), three (4%) and three (4%) isolates, respectively. E. coli isolates of phylogenetic group A were dominant (64%, 45/70). Pulsed field gel electrophoresis revealed none epidemiological relationship between these isolates. The results of this work report the higher frequency of Nal-resistant E. coli isolates from Moroccan retail food samples including MDR and pathogenic isolates.

  8. Prevalence of quinolone resistance mechanisms and associations to minimum inhibitory concentrations in quinolone-resistant Escherichia coli isolated from humans and swine in Denmark.

    Science.gov (United States)

    Cavaco, Lina Maria; Frimodt-Møller, Niels; Hasman, Henrik; Guardabassi, Luca; Nielsen, Lene; Aarestrup, Frank Møller

    2008-06-01

    Prevalence of quinolone resistance mechanisms and associations to minimum inhibitory concentrations (MICs) of nalidixic acid (NAL) and ciprofloxacin (CIP) were investigated in 124 Escherichia coli isolated from humans (n=85) and swine (n=39) in Denmark. The collection included 59 high-level CIP-resistant isolates (MIC >or= 4) from human (n=51) and pig origin (n=8) and 65 low-level CIP-resistant isolates (MIC >or= 0.125) from human (n=34) and pig origin (n=31). Resistance by target modification was screened by PCR amplification and sequencing of the quinolone resistance determining regions (QRDRs) of gyrA, gyrB, parC, and parE. QRDR mutations occurred in all except two isolates (98%). All high-level CIP-resistant E. coli had one or two mutations in gyrA in combination with mutations in parC or parE. Mutations in parC and parE were only found in combination with gyrA mutations, and no mutations were observed in gyrB. Efflux pump mechanisms were detected in 10 human (11.8%) and 29 porcine (74.4%) isolates by an efflux pump inhibitor (EPI) agar dilution assay. The aac(6')-Ib-cr gene mediating resistance by enzymatic modification was found in 12 high-level CIP-resistant human isolates. The qnrA and qnrS genes conferring quinolone resistance by target protection were detected in two human low-level CIP-resistant isolates that did not display NAL resistance. As expected, target mutation in QRDRs was the most prevalent mechanism of quinolone resistance. This mechanism was complemented by efflux mechanisms in most porcine isolates. Transferable resistance by target protection or enzymatic modification was less common (10%) and restricted to human isolates.

  9. [Investigation of plasmid-mediated quinolone resistance in Escherichia coli strains].

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    Aktepe, Orhan Cem; Aşık, Gülşah; Cetinkol, Yeliz; Biçmen, Meral; Gülay, Zeynep

    2012-01-01

    Quinolones are widely used antimicrobial agents, particularly for the treatment of infections caused by gram-negative bacilli such as E.coli. As a consequence, quinolone resistance has been increasing among this species in recent years. Bacterial resistance to quinolones usually results from mutations in the chromosomal genes which encode topoisomerases and also the expression of efflux pumps and loss of porines contributed to development of quinolone resistance. However, recent studies have shown that the spread and increase of quinolone resistance may be due to the transfer of plasmid-mediated genes. To date, three groups of plasmid-mediated quinolone resistance genes, namely qnr, aac(6')-Ib-cr, and qepA, have been described. The aim of this study was to investigate the presence of plasmid-mediated quinolone resistance genes in E.coli clinical isolates. A total of 112 quinolone-resistant E.coli strains isolated from different clinical specimens (84 urine, 16 blood, 10 wound, 2 bronchoalveolar lavage) of which 78 (69.6%) were extended-spectrum beta-lactamase (ESBL) positive, in Afyon Kocatepe University Hospital, Microbiology Laboratory were included in the study. In the isolates, qnrA, qnrB, qnrS, qnrC, qepA, and aac(6')-1b-cr plasmid genes were analysed by polymerase chain reaction (PCR). After aac(6')- 1b determinant was amplified by PCR, all aac(6')-1b positive amplicons were analyzed by digestion with BseGI restriction enzyme to identify aac(6')-1b-cr variant. It was found that, none of the strains horboured qnrA, qnrB, qnrS, qnrC and qepA genes, however, plasmid-mediated quinolone resistance gene aac(6')-1b-cr was found positive in 59.8% (67/112) of the strains. It was notable that 86.6% (58/67) of those isolates were ESBL producers. The rates of quinolone resistance among E.coli isolates infections were high in our region and an increasing trend has been observed in recent years. Our data indicated that the presence of plasmid- mediated resistance genes

  10. Dynamics of quinolone resistance in fecal Escherichia coli of finishing pigs after ciprofloxacin administration.

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    Huang, Kang; Xu, Chang-Wen; Zeng, Bo; Xia, Qing-Qing; Zhang, An-Yun; Lei, Chang-Wei; Guan, Zhong-Bin; Cheng, Han; Wang, Hong-Ning

    2014-09-01

    Escherichia coli resistance to quinolones has now become a serious issue in large-scale pig farms of China. It is necessary to study the dynamics of quinolone resistance in fecal Escherichia coli of pigs after antimicrobial administration. Here, we present the hypothesis that the emergence of resistance in pigs requires drug accumulation for 7 days or more. To test this hypothesis, 26 pigs (90 days old, about 30 kg) not fed any antimicrobial after weaning were selected and divided into 2 equal groups: the experimental (EP) group and control (CP) group. Pigs in the EP group were orally treated daily with 5 mg ciprofloxacin/kg of body weight for 30 days, and pigs in the CP group were fed a normal diet. Fresh feces were collected at 16 time points from day 0 to day 61. At each time point, ten E. coli clones were tested for susceptibility to quinolones and mutations of gyrA and parC. The results showed that the minimal inhibitory concentration (MIC) for ciprofloxacin increased 16-fold compared with the initial MIC (0.5 µg/ml) after ciprofloxacin administration for 3 days and decreased 256-fold compared with the initial MIC (0.5 µg/ml) after ciprofloxacin withdrawal for 26 days. GyrA (S83L, D87N/ D87Y) and parC (S80I) substitutions were observed in all quinolone-resistant E. coli (QREC) clones with an MIC ≥8 µg/ml. This study provides scientific theoretical guidance for the rational use of antimicrobials and the control of bacterial resistance.

  11. Cellular Response to Ciprofloxacin in Low-Level Quinolone-Resistant Escherichia coli

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    Jesús Machuca

    2017-07-01

    Full Text Available Bactericidal activity of quinolones has been related to a combination of DNA fragmentation, reactive oxygen species (ROS production and programmed cell death (PCD systems. The underlying molecular systems responsible for reducing bactericidal effect during antimicrobial therapy in low-level quinolone resistance (LLQR phenotypes need to be clarified. To do this and also define possible new antimicrobial targets, the transcriptome profile of isogenic Escherichia coli harboring quinolone resistance mechanisms in the presence of a clinical relevant concentration of ciprofloxacin was evaluated. A marked differential response to ciprofloxacin of either up- or downregulation was observed in LLQR strains. Multiple genes implicated in ROS modulation (related to the TCA cycle, aerobic respiration and detoxification systems were upregulated (sdhC up to 63.5-fold in mutants with LLQR. SOS system components were downregulated (recA up to 30.7-fold. yihE, a protective kinase coding for PCD, was also upregulated (up to 5.2-fold. SdhC inhibition sensitized LLQR phenotypes (up to ΔLog = 2.3 after 24 h. At clinically relevant concentrations of ciprofloxacin, gene expression patterns in critical systems to bacterial survival and mutant development were significantly modified in LLQR phenotypes. Chemical inhibition of SdhC (succinate dehydrogenase validated modulation of ROS as an interesting target for bacterial sensitization.

  12. [Investigation of plasmid-mediated quinolone resistance genes in quinolone-resistant Escherichia coli and Klebsiella spp. isolates from bloodstream infections].

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    Buruk, Celal Kurtuluş; Öztel Ocak, Hikmet; Bayramoğlu, Gülçin; Aydın, Faruk

    2016-04-01

    One of the treatment options of Escherichia coli and Klebsiella spp. infections which are the most common opportunistic pathogens of gram-negative sepsis is quinolones. Resistance to quinolones which act by disrupting DNA synthesis has been increasing. Horizontal transfer of plasmid-mediated quinolone resistance (PMQR) genes play an important role in the spread of resistance. The data about the prevalence of PMQR genes in our country is quite limited. The aim of this study was to investigate the presence of known PMQR genes namely qnrA, qnrB, qnrC, qnrS, qnrD, aac(6')-Ib-cr, qepA and oqxAB amongst quinolone-resistant E. coli and Klebsiella spp. strains isolated from blood cultures. One hundred twenty seven E.coli and 66 Klebsiella isolates detected as nalidixic acid- and/or ciprofloxacin-resistant by phenotypical methods, from 193 blood samples of 187 patients admitted to Karadeniz Technical University, Faculty of Medicine, Department of Medical Microbiology, Bacteriology Unit of Patient Service Laboratory between January 2012 to August 2013 were included in the study. The presence of PMQR genes were investigated by polymerase chain reaction (PCR) and for the detection of aac(6')-Ib-cr variants PCR-restriction fragment length polymorphism (PCR-RFLP) method was used. The positive bands were sequenced using the same primers, and aligned with formerly defined resistance gene sequences, and confirmed. In the study, 56.7% (72/127) of E.coli and 19.7% (13/66) of Klebsiella spp. isolates, with a total of 44% (85/193) of all the isolates were found to be phenotypically resistant to quinolones. Of the 13 resistant Klebsiella isolates, 11 were K.pneumoniae, and two were K.oxytoca. Extended-spectrum beta-lactamase (ESBL)-producing isolates showed higher resistance (50/80, 62.5%) to quinolones than the negative ones (35/113, 30.9%). The prevalence of quinolone resistance genes among resistant E. coli and Klebsiella spp. isolates was determined as qnrA, 1.4% and 15.4%; qnrB, 4

  13. Molecular epidemiological survey on quinolone resistance genotype and phenotype of Escherichia coli in septicemic broilers in Hebei, China.

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    Xie, Rong; Huo, Shuying; Li, Yurong; Chen, Ligong; Zhang, Feiyan; Wu, Xianjun

    2014-02-01

    In this study, the quinolone-resistant determining region (QRDR) of gyrA of Escherichia coli and plasmid-mediated quinolone resistance (PMQR) genes, qnr(qnrA, qnrB, and qnrS), and aac(6 ')-Ib-cr were detected, sequenced, and analyzed. In addition, antimicrobial susceptibility tests (using the Kirby-Bauer disc diffusion method) were performed for all 111 E. coli isolates from septicemic broilers in Hebei, China. The results show that the resistance rates were as follows: ofloxacin 99.10%, ciprofloxacin 93.69%, levofloxacin 91.89%, norfloxacin 90.09%, and gatifloxacin 76.58%. Of the PMQR genes examined, aac(6 ')-Ib-cr (36.04%) was the most frequently identified gene in all isolates, followed by qnrS (8.11%), qnrB (0.90%), and qnrA (0%). Of the QRDR examined in the 40 phenotypic quinolone-resistant isolates, compared with the gyrA(+) gene of E. coli K-12, 4 amino acid exchanges were found, namely Ser-83→Asp, Asp-87→Asn, Asp-87→Tyr, and Asp-87→Ala, and all 40 isolates had 1 or 2 exchanges in QRDR. It was concluded that quinolone-resistance in E. coli remains a serious problem in Hebei, China. Therefore, there is considerable local surveillance of quinolone resistance. Plasmid-mediated quinolone resistance of the qnr type remains rare in Hebei, China, and mutation in QRDR may be the main problem.

  14. Risk factors for quinolone-resistant Escherichia coli in feces from preweaned dairy calves and postpartum dairy cows.

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    Duse, Anna; Waller, Karin Persson; Emanuelson, Ulf; Unnerstad, Helle Ericsson; Persson, Ylva; Bengtsson, Björn

    2015-09-01

    Quinolone resistance may emerge in gut bacteria (e.g., in Escherichia coli) of animals. Such bacteria could cause infections in the animal itself or be transmitted to humans via the food chain. Quinolone resistance is also observed in fecal E. coli of healthy dairy cattle, but the prevalence varies between farms, not solely as a result of varying degree of fluoroquinolone exposure. The objective of this study was to identify risk factors for the fecal shedding of quinolone-resistant E. coli (QREC) from dairy calves and postpartum cows. Rectal swabs from 15 preweaned calves and 5 postpartum cows per farm were collected on 23 Swedish dairy farms to determine the prevalence of QREC. Risk factors for the shedding of QREC were investigated using multivariable statistical models. Quinolone-resistant E. coli were found on all but one farm. Factors associated with QREC shedding by calves were being younger than 18 d, being fed milk from cows treated with antimicrobials, recent use of fluoroquinolones in the herd, carriage of QREC by postpartum cows, and using the calving area never or rarely as a sick pen compared with often. Factors associated with QREC shedding by cows were calving in group pens or freestalls compared with single pens or tiestalls, purchasing cattle, sharing animal transports with other farmers, and poor farm hygiene. Proper biosecurity and improved hygiene, as well as minimizing fluoroquinolone exposure and waste milk feeding, may be important factors to reduce the burden of QREC on dairy farms.

  15. Prevalence of Plasmid-Mediated Quinolone Resistance Genes among Ciprofloxacin-Nonsusceptible Escherichia coli and Klebsiella pneumoniae Isolated from Blood Cultures in Korea

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    Hee Young Yang

    2014-01-01

    Full Text Available OBJECTIVES:To analyze the prevalence of plasmid-mediated quinolone resistance (PMQR determinants in ciprofloxacin-nonsusceptible Escherichia coli and Klebsiella pneumoniae isolated from patients at a tertiary care hospital in Korea.

  16. Comparative Analysis of Quinolone Resistance in Clinical Isolates of Klebsiella pneumoniae and Escherichia coli from Chinese Children and Adults

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    Ying Huang

    2015-01-01

    Full Text Available The objective of this study was to compare quinolone resistance and gyrA mutations in clinical isolates of Klebsiella pneumoniae and Escherichia coli from Chinese adults who used quinolone in the preceding month and children without any known history of quinolone administration. The antimicrobial susceptibilities of 61 isolates from children and 79 isolates from adults were determined. The mutations in the quinolone resistance-determining regions in gyrA gene were detected by PCR and DNA sequencing. Fluoroquinolone resistance and types of gyrA mutations in isolates from children and adults were compared and statistically analyzed. No significant differences were detected in the resistance rates of ciprofloxacin and levofloxacin between children and adults among isolates of the two species (all P>0.05. The double mutation Ser83→Leu + Asp87→Asn in the ciprofloxacin-resistant isolates occurred in 73.7% isolates from the children and 67.9% from the adults, respectively (P=0.5444. Children with no known history of quinolone administration were found to carry fluoroquinolone-resistant Enterobacteriaceae isolates. The occurrence of ciprofloxacin resistance and the major types of gyrA mutations in the isolates from the children were similar to those from adults. The results indicate that precautions should be taken on environmental issues resulting from widespread transmission of quinolone resistance.

  17. Comparative analysis of quinolone resistance in clinical isolates of Klebsiella pneumoniae and Escherichia coli from Chinese children and adults.

    Science.gov (United States)

    Huang, Ying; Ogutu, James O; Gu, Jiarui; Ding, Fengshu; You, Yuhong; Huo, Yan; Zhao, Hong; Li, Wenjing; Zhang, Zhiwei; Zhang, Wenli; Chen, Xiaobei; Fu, Yingmei; Zhang, Fengmin

    2015-01-01

    The objective of this study was to compare quinolone resistance and gyrA mutations in clinical isolates of Klebsiella pneumoniae and Escherichia coli from Chinese adults who used quinolone in the preceding month and children without any known history of quinolone administration. The antimicrobial susceptibilities of 61 isolates from children and 79 isolates from adults were determined. The mutations in the quinolone resistance-determining regions in gyrA gene were detected by PCR and DNA sequencing. Fluoroquinolone resistance and types of gyrA mutations in isolates from children and adults were compared and statistically analyzed. No significant differences were detected in the resistance rates of ciprofloxacin and levofloxacin between children and adults among isolates of the two species (all P > 0.05). The double mutation Ser83→Leu + Asp87→Asn in the ciprofloxacin-resistant isolates occurred in 73.7% isolates from the children and 67.9% from the adults, respectively (P = 0.5444). Children with no known history of quinolone administration were found to carry fluoroquinolone-resistant Enterobacteriaceae isolates. The occurrence of ciprofloxacin resistance and the major types of gyrA mutations in the isolates from the children were similar to those from adults. The results indicate that precautions should be taken on environmental issues resulting from widespread transmission of quinolone resistance.

  18. Occurrence of plasmid-mediated quinolone resistance and virulence genes in avian Escherichia coli isolates from Algeria.

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    Laarem, Meradi; Barguigua, Abouddihaj; Nayme, Kaotar; Akila, Abdi; Zerouali, Khalid; El Mdaghri, Naima; Timinouni, Mohammed

    2017-02-28

    The emergence and spread of quinolone-resistant Escherichia coli in poultry products puts consumers at risk of exposure to the strains of E. coli that resist antibiotic treatment. The objective of this study was to define the prevalence and virulence potential of poultry-associated nalidixic acid (NAL)-resistant E. coli in the Annaba city, Algeria. In total, 33 samples of retail chicken meat were purchased from various butcher shops and examined for bacterial contamination with NAL-resistant E. coli. These isolates were subjected to antimicrobial susceptibility testing and were also investigated for the presence of plasmid-mediated quinolone resistance (PMQR) genes and virulence genes using conventional polymerase chain reaction (PCR) and DNA sequencing. Phylogenetic grouping of the NAL-resistant E. coli isolates was determined by the conventional multiplex PCR method. Twenty-nine (87.8%) products yielded NAL-resistant E. coli. Antibiograms revealed that 96.55% of NAL-resistant E. coli isolates were multidrug resistant (MDR). Resistance was most frequently observed against sulfamethoxazole-trimethoprim (96.6%), tetracycline (96.6%), ciprofloxacin (72%), and amoxicillin (65.5%). Group A was the most prevalent phylogenetic group, followed by groups D, B1, and B2. The PMQR determinants were detected in three isolates with qnrB72 and qnrS1 type identified. Four (13.8%) isolates carried one of the Shiga toxin E. coli-associated genes stx1, stx2, and ehxA alleles. The high prevalence of NAL-resistant E. coli isolated from retail chicken meat with detection of MDR E. coli harboring Shiga toxin genes in this study gives a warning signal for possible occurrence of foodborne infections with failure in antibiotic treatment.

  19. Plasmid-related quinolone resistance determinants in epidemic Vibrio parahaemolyticus, uropathogenic Escherichia coli, and marine bacteria from an aquaculture area in Chile.

    Science.gov (United States)

    Aedo, Sandra; Ivanova, Larisa; Tomova, Alexandra; Cabello, Felipe C

    2014-08-01

    Marine bacteria from aquaculture areas with industrial use of quinolones have the potential to pass quinolone resistance genes to animal and human pathogens. The VPA0095 gene, related to the quinolone resistance determinant qnrA, from clinical isolates of epidemic Vibrio parahaemolyticus conferred reduced susceptibility to quinolone after cloning into Escherichia coli K-12 either when acting alone or synergistically with DNA gyrase mutations. In addition, a plasmid-mediated quinolone resistance gene from marine bacteria, aac(6')-Ib-cr, was identical to aac(6')-Ib-cr from urinary tract isolates of E. coli, suggesting a recent flow of this gene between these bacteria isolated from different environments. aac(6')-Ib-cr from E. coli also conferred reduced susceptibility to quinolone and kanamycin when cloned into E. coli K-12.

  20. Prevalence and characteristics of quinolone resistance in Escherichia coli in veal calves

    NARCIS (Netherlands)

    Hordijk, J.; Veldman, K.T.; Dierikx, C.M.; Essen-Zandbergen, van A.; Wagenaar, J.A.; Mevius, D.J.

    2012-01-01

    Quinolone resistance is studied and reported increasingly in isolates from humans, food-producing animals and companion animals. Resistance can be caused by chromosomal mutations in topoisomerase genes, plasmid-mediated resistance genes, and active transport through efflux pumps. Cross sectional dat

  1. Prevalence and characteristics of quinolone resistance in Escherichia coli in veal calves

    NARCIS (Netherlands)

    Hordijk, J.; Veldman, K.T.; Dierikx, C.M.; Essen-Zandbergen, van A.; Wagenaar, J.A.; Mevius, D.J.

    2012-01-01

    Quinolone resistance is studied and reported increasingly in isolates from humans, food-producing animals and companion animals. Resistance can be caused by chromosomal mutations in topoisomerase genes, plasmid-mediated resistance genes, and active transport through efflux pumps. Cross sectional dat

  2. Characteristics of Quinolone Resistance in Escherichia coli Isolates from Humans, Animals, and the Environment in the Czech Republic

    Science.gov (United States)

    Röderova, Magdalena; Halova, Dana; Papousek, Ivo; Dolejska, Monika; Masarikova, Martina; Hanulik, Vojtech; Pudova, Vendula; Broz, Petr; Htoutou-Sedlakova, Miroslava; Sauer, Pavel; Bardon, Jan; Cizek, Alois; Kolar, Milan; Literak, Ivan

    2017-01-01

    Escherichia coli is a common commensal bacterial species of humans and animals that may become a troublesome pathogen causing serious diseases. The aim of this study was to characterize the quinolone resistance phenotypes and genotypes in E. coli isolates of different origin from one area of the Czech Republic. E. coli isolates were obtained from hospitalized patients and outpatients, chicken farms, retailed turkeys, rooks wintering in the area, and wastewaters. Susceptibility of the isolates grown on the MacConkey agar with ciprofloxacin (0.05 mg/L) to 23 antimicrobial agents was determined. The presence of plasmid-mediated quinolone resistance (PMQR) and ESBL genes was tested by PCR and sequencing. Specific mutations in gyrA, gyrB, parC, and parE were also examined. Multilocus sequence typing and pulsed-field gel electrophoresis were performed to assess the clonal relationship. In total, 1050 E. coli isolates were obtained, including 303 isolates from humans, 156 from chickens, 105 from turkeys, 114 from the rooks, and 372 from wastewater samples. PMQR genes were detected in 262 (25%) isolates. The highest occurrence was observed in isolates from retailed turkey (49% of the isolates were positive) and inpatients (32%). The qnrS1 gene was the most common PMQR determinant identified in 146 (56%) followed by aac(6′)-Ib-cr in 77 (29%), qnrB19 in 41 (16%), and qnrB1 in 9 (3%) isolates. All isolates with high level of ciprofloxacin resistance (>32 mg/L) carried double or triple mutations in gyrA combined with single or double mutations in parC. The most frequently identified substitutions were Ser(83)Leu; Asp(87)Asn in GyrA, together with Ser(80)Ile, or Glu(84)Val in ParC. Majority of these isolates showed resistance to beta-lactams and multiresistance phenotype was found in 95% isolates. Forty-eight different sequence types among 144 isolates analyzed were found, including five major clones ST131 (26), ST355 (19), ST48 (13), ST95 (10), and ST10 (5). No isolates

  3. Antimalarial therapy selection for quinolone resistance among Escherichia coli in the absence of quinolone exposure, in tropical South America.

    Directory of Open Access Journals (Sweden)

    Ross J Davidson

    Full Text Available BACKGROUND: Bacterial resistance to antibiotics is thought to develop only in the presence of antibiotic pressure. Here we show evidence to suggest that fluoroquinolone resistance in Escherichia coli has developed in the absence of fluoroquinolone use. METHODS: Over 4 years, outreach clinic attendees in one moderately remote and five very remote villages in rural Guyana were surveyed for the presence of rectal carriage of ciprofloxacin-resistant gram-negative bacilli (GNB. Drinking water was tested for the presence of resistant GNB by culture, and the presence of antibacterial agents and chloroquine by HPLC. The development of ciprofloxacin resistance in E. coli was examined after serial exposure to chloroquine. Patient and laboratory isolates of E. coli resistant to ciprofloxacin were assessed by PCR-sequencing for quinolone-resistance-determining-region (QRDR mutations. RESULTS: In the very remote villages, 4.8% of patients carried ciprofloxacin-resistant E. coli with QRDR mutations despite no local availability of quinolones. However, there had been extensive local use of chloroquine, with higher prevalence of resistance seen in the villages shortly after a Plasmodium vivax epidemic (p<0.01. Antibacterial agents were not found in the drinking water, but chloroquine was demonstrated to be present. Chloroquine was found to inhibit the growth of E. coli in vitro. Replica plating demonstrated that 2-step QRDR mutations could be induced in E. coli in response to chloroquine. CONCLUSIONS: In these remote communities, the heavy use of chloroquine to treat malaria likely selected for ciprofloxacin resistance in E. coli. This may be an important public health problem in malarious areas.

  4. Molecular characterization of quinolone resistance mechanisms and extended-spectrum β-lactamase production in Escherichia coli isolated from dogs.

    Science.gov (United States)

    Meireles, D; Leite-Martins, L; Bessa, L J; Cunha, S; Fernandes, R; de Matos, A; Manaia, C M; Martins da Costa, P

    2015-08-01

    The increasing prevalence of antimicrobial resistances is now a worldwide problem. Investigating the mechanisms by which pets harboring resistant strains may receive and/or transfer resistance determinants is essential to better understanding how owners and pets can interact safely. Here, we characterized the genetic determinants conferring resistance to β-lactams and quinolones in 38 multidrug-resistant Escherichia coli isolated from fecal samples of dogs, through PCR and sequencing. The most frequent genotype included the β-lactamase groups TEM (n=5), and both TEM+CTX-M-1 (n=5). Within the CTX-M group, we identified the genes CTX-M-32, CTX-M-1, CTX-M-15, CTX-M-55/79, CTX-M-14 and CTX-M-2/44. Thirty isolates resistant to ciprofloxacin presented two mutations in the gyrA gene and one or two mutations in the parC gene. A mutation in gyrA (reported here for the first time), due to a transversion and transition (TCG→GTG) originating a substitution of a serine by a valine in position 83 was also detected. The plasmid-encoded quinolone resistance gene, qnrs1, was detected in three isolates. Dogs can be a reservoir of genetic determinants conferring antimicrobial resistance and thus may play an important role in the spread of antimicrobial resistance to humans and other co-habitant animals.

  5. Plasmid-Mediated Quinolone Resistance in Escherichia coli Isolates from Wild Birds and Chickens in South Korea.

    Science.gov (United States)

    Oh, Jae-Young; Kwon, Yong-Kuk; Tamang, Migma Dorji; Jang, Hyung-Kwan; Jeong, Ok-Mi; Lee, Hee-Soo; Kang, Min-Su

    2016-01-01

    A total of 2,423 nonduplicate isolates of Escherichia coli recovered from wild birds (n=793) and chickens (n=1,630) in South Korea were investigated for plasmid-mediated quinolone resistance (PMQR) genes. Altogether, 56 isolates with PMQR genes were identified, including 25 (3.2%) from wild birds and 31 (1.9%) from chickens, which were further characterized using molecular methods. Among them, qnrS, aac(6')-Ib-cr, qnrB, and qepA genes were detected in 47 (1.9%), 6 (0.24%), 2 (0.08%), and 1 (0.04%) isolates, respectively. The most prevalent gene, qnrS, was identified in 21 (0.9%) and 26 (1.1%) isolates from wild birds and chickens, respectively. The qnrB gene was identified in two chicken isolates, which included qnrB19 and a novel qnrB44 gene. Plasmid isolation and Southern hybridization revealed that qnrS1 was located on a large (>200 kbp) plasmid. The spread of the PMQR genes was attributed to a combination of horizontal dissemination and clonal expansion. The horizontal dissemination of PMQR genes was mostly mediated by IncK plasmids. Molecular typing demonstrated that the majority of the PMQR-positive isolates were genetically diverse. Only one chicken isolate belonged to ST131, which harbored an additional CMY-2 gene. Our findings suggest that the wild birds could serve as reservoirs of PMQR genes and spread them over long distances through migration. To our knowledge, this is the first report of PMQR genes in Korean wild birds. This study also reports qnrS2, qnrB19, qnrB44, and qepA genes for the first time in animal E. coli isolates from South Korea.

  6. Determinants of quinolone resistance in Escherichia coli causing community-acquired urinary tract infection in Bejaia, Algeria.

    Science.gov (United States)

    Betitra, Yanat; Teresa, Vinuesa; Miguel, Viñas; Abdelaziz, Touati

    2014-06-01

    To investigate the mechanisms of quinolone resistance and the association with other resistance markers among Esherichia coli (E. coli) strains isolated from outpatient with urinary tract infection in north of Algeria. A total of 30 nalidixic acid-resistant E. coli isolates from outpatient with urinary tract infections from January 2010 to April 2011 in north of Algeria (Bejaia) were studied. Antimicrobial susceptibility was determined by disc diffusion assay, minimal inhibitory concentrations (MIC) of quinolone were determined by microdilution. Mutations in the Quinolone Resistance-Determining Region (QRDR) of gyrA and parC genes and screening for qnr (A, B and S) and bla genes were done by PCR and DNA sequencing. Most of the E. coli isolates (56.66%) were shown to carry mutations in gyrA and parC (gyrA: Ser83Leu + Asp87Asn and parC:Ser80Ile). While, 16.66% had only an alteration in gyrA: Ser83Leu. One isolate produced qnrB-like and two qnrS-like. Four isolates were CTX-M-15 producers associated with TEM-1 producing in one case. Co-expression of blaCTX-M-15 and qnrB was determined in one E. coli isolate. Our findings suggested the community emergence of gyrA and parC alterations and Qnr determinants that contributed to the development and spread of fluoroquinolone resistance in Algerian E. coli isolates. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  7. Occurrence of Extended-Spectrum β-Lactamases, Plasmid-Mediated Quinolone Resistance, and Disinfectant Resistance Genes in Escherichia coli Isolated from Ready-To-Eat Meat Products

    DEFF Research Database (Denmark)

    Li, Lili; Ye, Lei; Kromann, Sofie

    2017-01-01

    There are growing concerns about the coselection of resistance against antibiotics and disinfectants in bacterial pathogens. The aim of this study was to characterize the antimicrobial susceptibility profiles, the prevalence of extended-spectrum β-lactamases (ESBLs), plasmid-mediated quinolone...... resistance genes (PMQRs), and quaternary ammonium compound resistance genes (QACs) in Escherichia coli isolated from ready-to-eat (RTE) meat products obtained in Guangzhou, China, and to determine whether these genes were colocalized in the isolates. A total of 64 E. coli isolates were obtained from 720 RTE...... meat samples. Multidrug resistance was observed in 70.3% of the isolates. A 100% of the isolates were resistant to benzalkonium chloride. Four types of β-lactamase genes were identified in the 16 ESBL-producing E. coli isolates: blaSHV (9.4%), blaTEM (7.8%), blaCTX-M-15 (1.6%), and blaCTX-M-9 (1...

  8. Characterization of ESBLs and associated quinolone resistance in Escherichia coli and Klebsiella pneumoniae isolates from an urban wastewater treatment plant in Algeria.

    Science.gov (United States)

    Alouache, Souhila; Estepa, Vanesa; Messai, Yamina; Ruiz, Elena; Torres, Carmen; Bakour, Rabah

    2014-02-01

    The aim of the study was the characterization of extended spectrum beta-lactamases (ESBLs) and quinolone resistance in cefotaxime-resistant coliform isolates from a wastewater treatment plant (WWTP). ESBLs were detected in 19 out of 24 isolates (79%) from raw water and in 21 out of 24 isolates (87.5%) from treated water, identified as Klebsiella pneumoniae and Escherichia coli. Molecular characterization of ESBLs and quinolone resistance showed allele profiles CTX-M-15 (3), CTX-M-3 (5), CTX-M-15+qnrB1 (1), CTX-M-3+qnrB1 (1), CTX-M-15+aac-(6')-Ib-cr (4), and CTX-M-15+qnrB1+aac-(6')-Ib-cr (7). A double mutation S83L and D87N (GyrA) and a single mutation S80I (ParC) were detected in ciprofloxacin-resistant E. coli isolates. In K. pneumoniae, mutations S83I (GyrA)+S80I (ParC) or single S80I mutation were detected in ciprofloxacin-resistant isolates, and no mutation was observed in ciprofloxacin-susceptible isolates. bla(CTX-M), qnrB1, and aac-(6')-Ib-cr were found, respectively, in these genetic environments: ISEcp1-bla(CTX-M)-orf477, orf1005-orf1-qnrB1, and Tn1721-IS26-aac-(6')-Ib-cr-bla(OXA-1)-catB4. bla(CTX-M-15) was located on IncF plasmid in E. coli and bla(CTX-M-3) on IncL/M plasmid in both species (E. coli and K. pneumoniae). E. coli isolates were affiliated to the phylogroups/MLST: D/ST405 (CC405), A/ST10 (CC10), A/ST617 (CC10), and B1/ST1431. K. pneumoniae isolates belonged to phylogroup KpI and to sequence types ST15, ST17, ST36, ST48, ST54, and ST147. The study showed a multi-drug resistance at the inflow and outflow of the WWTP, with ESBL production, plasmid-mediated quinolones resistance, and mutations in topoisomerases. The findings highlight the similarity of antibiotic resistance mechanisms in the clinical setting and the environment, and the role of the latter as a source of dissemination of resistance genes.

  9. Quinolone resistance and ESBL/AmpC’s in commensal Escherichia coli in veal calves : prevalence and molecular characterization

    NARCIS (Netherlands)

    Hordijk, J.

    2013-01-01

    In this thesis the prevalence and molecular characteristics of resistance to (fluoro)quinolones and Extended Spectrum Cephalosporins (ESC) in veal calves were described using Escherichia coli as an indicator organism. Ciprofloxacin and nalidixic acid were used as indicator antimicrobials for quinolo

  10. Quinolone resistance and ESBL/AmpC’s in commensal Escherichia coli in veal calves : prevalence and molecular characterization

    NARCIS (Netherlands)

    Hordijk, J.

    2013-01-01

    In this thesis the prevalence and molecular characteristics of resistance to (fluoro)quinolones and Extended Spectrum Cephalosporins (ESC) in veal calves were described using Escherichia coli as an indicator organism. Ciprofloxacin and nalidixic acid were used as indicator antimicrobials for quinolo

  11. Extended spectrum β-lactamase and plasmid mediated quinolone resistance in Escherichia coli fecal isolates from healthy companion animals in Algeria.

    Science.gov (United States)

    Yousfi, Massilia; Mairi, Assia; Touati, Abdelaziz; Hassissene, Lila; Brasme, Lucien; Guillard, Thomas; De Champs, Christophe

    2016-07-01

    The aim of this study was to evaluate the rate of fecal carriage of Escherichia coli strains producing Extended-spectrum β-lactamases (ESBLs) and plasmid-mediated quinolone resistance (PMQR) isolated from healthy pets (dogs and cats) in Algeria. Fecal samples from 171 healthy pets (102 dogs and 69 cats) in one veterinary practice and private owners were included. After isolates identification, antibiotic susceptibility was determined by disk diffusion procedure. ESBL were detected by combination disk tests. PCR and sequencing were used to characterize genes encoding ESBLs and PMQR. Transfer of ESBL and PMQR genes was assessed by conjugation experiments. Phylogenetic groups of E. coli were determined by PCR. Of the 171 animals, 20 carried an ESBL producing E. coli giving a prevalence of ESBL fecal carriage of 11.7%. All isolates were susceptible to carbapenems, cefoxitin, piperacillin-tazobactam, amikacin and fosfomycine. For the rest of the tested β-lactams, susceptibility rates ranged from 35% to 70% for cefepime and amoxicillin-clavulanic acid respectively. Concerning the non-beta-lactams antibiotics, the rates of susceptibility ranged between 5% to trimethoprim and 95% for chloramphenicol. The beta-lactamase genes identified in E. coli isolates were blaCTX-M-15, blaCTX-M-1, blaSHV-12 and blaTEM-1. The PMQR determinants aac(6')-Ib-cr, qnrS1 and qnrB5 genes were identified in 15 isolates. Transconjugants were obtained for two isolates. Phylogenetic analysis showed that E. coli isolates belong to commensal phylogroups of A and B1. We reported here for the first time in Algeria ESBL and PMQR-producing E. coli in healthy cats and dogs.

  12. High Prevalence of β-lactamase and Plasmid-Mediated Quinolone Resistance Genes in Extended-Spectrum Cephalosporin-Resistant Escherichia coli from Dogs in Shaanxi, China

    Science.gov (United States)

    Liu, Xiaoqiang; Liu, Haixia; Li, Yinqian; Hao, Caiju

    2016-01-01

    Objective: The aim of this study was to investigate the occurrence and molecular characterization of extended-spectrum β-lactamases (ESBL), plasmid-mediated AmpC β-lactamase (pAmpC) and carbapenemases as well as plasmid-mediated quinolone-resistant (PMQR) among extended-spectrum cephalosporin-resistant (ESC-R) Escherichia coli from dogs in Shaanxi province in China. Methods: A total of 40 ESC-R Escherichia coli selected from 165 Extraintestinal pathogenic E. coli (ExPEC) isolated from dogs were screened and characterized for the genes encoding for the ESBLs, pAmpC, carbapenemases and PMQR genes by PCR and sequencing. Phylogenetic groups, virulence gene profiles and multilocus sequence typing (MLST) were used to investigate the genetic background of the ESC-R E. coli isolates. Results: Among 40 ESC-R E. coli, the predominant β-lactamase gene was blaCTX−Ms (n = 35), and followed by blaTEM−1 (n = 31), blaSHV−12 (n = 14), blaOXA−48 (n = 8), blaTEM−30 (n = 4), blaCMY−2 (n = 3) and blaDHA−1 (n = 2). The most common specific blaCTX−M gene subtype was blaCTX−M−15 (n = 31), and followed by blaCTX−M−123 (n = 14), blaCTX−M−1 (n = 10), blaCTX−M−14 (n = 10) and blaCTX−M−9 (n = 7). PMQR genes were detected in 32 (80%) isolates, and the predominant PMQR gene was aac(6′)-Ib-cr (n = 26), followed by qnrS (n = 12), qnrD (n = 9), qnrB (n = 8), qepA (n = 4), and all PMQR genes were detected in co-existence with β-lactamase genes. traT (n = 34) and fimH (n = 32) were the most prevalent virulence genes, and virulence genes fimH, iutA, fyuA, malX, iha, and sat were more prevalent in phylogenetic group B2. The 40 ESC-R isolates analyzed were assigned to 22 sequence types (STs), and the clonal lineages ST131 (n = 10) and ST10 (n = 9) were the predominant STs. Conclusion: High prevalence of β-lantamases and PMQR genes were detected among ESC-R E. coli from companion animals. This is also the first description of the co-existence of six

  13. High Prevalence of β-lactamase and Plasmid-mediated Quinolone Resistance Genes in Extended-spectrum Cephalosporin-resistant Escherichia coli from Dogs in Shaanxi, China

    Directory of Open Access Journals (Sweden)

    Xiaoqiang Liu

    2016-11-01

    Full Text Available Objective: The aim of this study was to investigate the occurrence and molecular characterization of extended-spectrum β-lactamases (ESBL, plasmid-mediated AmpC β-lactamase (pAmpC and carbapenemases as well as plasmid-mediated quinolone-resistant (PMQR among extended-spectrum cephalosporin-resistant (ESC-R Escherichia coli from dogs in Shaanxi province in China.Methods: A total of 40 ESC-R Escherichia coli selected from 165 Extraintestinal pathogenic E. coli (ExPEC isolated from dogs were screened and characterized for the genes encoding for the ESBLs, pAmpC, carbapenemases and PMQR genes by PCR and sequencing. Phylogenetic groups, virulence gene profiles and multilocus sequence typing (MLST were used to investigate the genetic background of the ESC-R E. coli isolates. Results: Among 40 ESC-R E. coli, the predominant β-lactamase gene was blaCTX-Ms (n=35, and followed by blaTEM-1 (n=31, blaSHV-12 (n=14, blaOXA-48 (n=8, blaTEM-30 (n=4, blaCMY-2 (n=3 and blaDHA-1 (n=2. The most common specific blaCTX-M gene subtype was blaCTX-M-15 (n=31, and followed by blaCTX-M-123 (n=14, blaCTX-M-1 (n=10, blaCTX-M-14 (n=10 and blaCTX-M-9 (n=7. PMQR genes were detected in 32 (80% isolates, and the predominant PMQR gene was aac(6'-Ib-cr (n=26, followed by qnrS (n=12, qnrD (n=9, qnrB (n=8, qepA (n=4, and all PMQR genes were detected in co-existence with β-lactamase genes. traT (n=34 and fimH (n=32 were the most prevalent virulence genes, and virulence genes fimH, iutA, fyuA, malX, iha and sat were more prevalent in phylogenetic group B2. The 40 ESC-R isolates analyzed were assigned to 22 sequence types (STs, and the clonal lineages ST131 (n=10 and ST10 (n=9 were the predominant STs. Conclusion: High prevalence of β-lantamases and PMQR genes were detected among ESC-R E. coli from companion animals. This is also the first description of the co-existence of six β-lantamase genes and five PMQR genes in one E. coli isolate. Moreover, ten ST131 clones harboring CTX

  14. In vivo sequential selection of Escherichia coli with topoisomerase- and efflux-mediated misleading quinolone resistance phenotypes.

    Science.gov (United States)

    Smati, Mounira; Emond, Jean-Philippe; Arlet, Guillaume; Tankovic, Jacques

    2012-02-01

    Two mutants of Escherichia coli (V1 and V2) with acquired mechanisms of resistance to fluoroquinolones were isolated sequentially from blood cultures of a patient with cholangiocarcinoma treated repeatedly with ofloxacin; a third mutant (V3) was isolated under ciprofloxacin therapy. All mutants were related clonally. V1 was susceptible to quinolones but with diminished susceptibility to ofloxacin. V2 was hypersusceptible to nalidixic acid but had high-level resistance to ofloxacin. V3 was resistant to all quinolones. Ofloxacin selected for original gyrA and parC mutations, leading to the unusual and misleading resistance phenotypes of V1 and V2, whereas efflux played a major role in the increased resistance of V3.

  15. 喹诺酮耐药大肠埃希菌尿道感染现状及危险因素分析%Quinolone resistant Escherichia coli isolated from urinary tract infection:clinical status and risk factors

    Institute of Scientific and Technical Information of China (English)

    张安兵

    2012-01-01

    Objective To investigate the quinolone resistant Escherkhia coli infection status and risk factors, and provide a basis for selecting appropriate antibiotics in the clinical practice. Methods This study is a retrospective review from 2010 to 2011. 348 strains Escherichia coli isolated from urine specimens were analysis, using the quinolone susceptible isolates as the control group. The risk factors for the quinolone resistance strains were analyzed. Results Of the 348 E.coli strains isolated from urinary tract infection patient, 58.3% (203)were quinolone resistant. Logistic regression analysis showed three generation cephalosporins and quinolones drug use, urinary drainage and bacterium producing extra-broad spectrum beta-lactamase were the independent risk factors for ciprofloxacin resistance of E.coli strains isolated from urinary tract infection patients. Conclusion The epidemic of quinolone resistant Escherichia coli isolated from urine specimens were extremely serious. The drug resistance of the quinolone resistant isolates was strong. The patients infected with quinolone resistant strains had high medical cost and longer average length of stay in hospital. The quinolone resistant E.coli infection with multiple independent risk factors, the strengthening of these independent risk factor controls can effectively prevent the spread of quinolone resistant strains infection.%目的 分析喹诺酮耐药大肠埃希菌尿道感染现状及危险因素,为临床合理选用抗生素提供依据.方法 回顾性分析348例大肠埃希菌尿道感染临床现状,以喹诺酮敏感大肠埃希菌为对照菌株,对喹诺酮耐药大肠埃希菌感染危险因素进行分析.结果 348株大肠埃希菌尿道感染中检出喹诺酮耐药菌203株,占58.3%.Logistic回归分析显示三代头孢菌素及喹诺酮类药物使用、尿路引流和细菌产超广谱β-内酰胺酶是喹诺酮耐药大肠埃希菌感染的独立危险因素.结论 尿道感染大肠埃

  16. The Magnitude of the Association between Fluoroquinolone Use and Quinolone-Resistant Escherichia coli and Klebsiella pneumoniae May Be Lower than Previously Reported

    OpenAIRE

    Bolon, Maureen K.; Wright, Sharon B.; Gold, Howard S.; Carmeli, Yehuda

    2004-01-01

    Case-control analyses of resistant versus susceptible isolates have implicated fluoroquinolone exposure as a strong risk factor for fluoroquinolone-resistant isolates of Enterobacteriaceae. We suspect that such methodology may overestimate this association. A total of 84 cases with fluoroquinolone-resistant isolates and 578 cases with fluoroquinolone-susceptible isolates of Escherichia coli or Klebsiella pneumoniae were compared with 608 hospitalized controls in parallel multivariable analyse...

  17. Mechanisms of quinolone resistance in Escherichia coli: characterization of nfxB and cfxB, two mutant resistance loci decreasing norfloxacin accumulation.

    Science.gov (United States)

    Hooper, D C; Wolfson, J S; Souza, K S; Ng, E Y; McHugh, G L; Swartz, M N

    1989-03-01

    Two genetic loci selected for norfloxacin (nfxB) and ciprofloxacin (cfxB) resistance were characterized. Both mutations have previously been shown to confer pleiotropic resistance to quinolones, chloramphenicol, and tetracycline and to decrease expression of porin outer-membrane protein OmpF. nfxB was shown to map at about 19 min and thus to be genetically distinct from ompF (21 min), and cfxB was shown to be very closely linked to marA (34 min). cfxB was dominant over cfxB+ in merodiploids, in contrast to other quinolone resistance mutations. The two loci appear to interact functionally, because nfxB was not expressed in the presence of marA::Tn5. Both nfxB and cfxB decreased the expression of ompF up to 50-fold at the posttranscriptional level as determined in strains containing ompF-lacZ operon and protein fusions. Both mutations also decreased norfloxacin accumulation in intact cells. This decrease in accumulation was abolished by energy inhibitors and by removal of the outer membrane. These findings, in conjunction with those of Cohen et al. (S. P. Cohen, D. C. Hooper, J. S. Wolfson, K. S. Souza, L. M. McMurry, and S. B. Levy, Antimicrob. Agents Chemother. 32:1187-1191, 1988), suggest a model for quinolone resistance by decreased permeation in which decreased diffusion through porin channels in the outer membrane interacts with a saturable drug efflux system at the inner membrane.

  18. Seawater is a reservoir of multi-resistant Escherichia coli, including strains hosting plasmid-mediated quinolones resistance and extended-spectrum beta-lactamases genes.

    Science.gov (United States)

    Alves, Marta S; Pereira, Anabela; Araújo, Susana M; Castro, Bruno B; Correia, António C M; Henriques, Isabel

    2014-01-01

    The aim of this study was to examine antibiotic resistance (AR) dissemination in coastal water, considering the contribution of different sources of fecal contamination. Samples were collected in Berlenga, an uninhabited island classified as Natural Reserve and visited by tourists for aquatic recreational activities. To achieve our aim, AR in Escherichia coli isolates from coastal water was compared to AR in isolates from two sources of fecal contamination: human-derived sewage and seagull feces. Isolation of E. coli was done on Chromocult agar. Based on genetic typing 414 strains were established. Distribution of E. coli phylogenetic groups was similar among isolates of all sources. Resistances to streptomycin, tetracycline, cephalothin, and amoxicillin were the most frequent. Higher rates of AR were found among seawater and feces isolates, except for last-line antibiotics used in human medicine. Multi-resistance rates in isolates from sewage and seagull feces (29 and 32%) were lower than in isolates from seawater (39%). Seawater AR profiles were similar to those from seagull feces and differed significantly from sewage AR profiles. Nucleotide sequences matching resistance genes bla TEM, sul1, sul2, tet(A), and tet(B), were present in isolates of all sources. Genes conferring resistance to 3rd generation cephalosporins were detected in seawater (bla CTX-M-1 and bla SHV-12) and seagull feces (bla CMY-2). Plasmid-mediated determinants of resistance to quinolones were found: qnrS1 in all sources and qnrB19 in seawater and seagull feces. Our results show that seawater is a relevant reservoir of AR and that seagulls are an efficient vehicle to spread human-associated bacteria and resistance genes. The E. coli resistome recaptured from Berlenga coastal water was mainly modulated by seagulls-derived fecal pollution. The repertoire of resistance genes covers antibiotics critically important for humans, a potential risk for human health.

  19. Seawater is a reservoir of multi-resistant Escherichia coli, including strains hosting plasmid-mediated quinolones resistance and extended-spectrum beta-lactamases genes

    Directory of Open Access Journals (Sweden)

    Marta S. Alves

    2014-08-01

    Full Text Available The aim of this study was to examine antibiotic resistance (AR dissemination in coastal water, considering the contribution of different sources of faecal contamination. Samples were collected in Berlenga, an uninhabited island classified as Natural Reserve and visited by tourists for aquatic recreational activities. To achieve our aim, AR in Escherichia coli isolates from coastal water was compared to AR in isolates from two sources of faecal contamination: human-derived sewage and seagull faeces. Isolation of E. coli was done on Chromocult agar. Based on genetic typing 414 strains were established. Distribution of E. coli phylogenetic groups was similar among isolates of all sources. Resistances to streptomycin, tetracycline, cephalothin and amoxicillin were the most frequent. Higher rates of AR were found among seawater and faeces isolates, except for last-line antibiotics used in human medicine. Multi-resistance rates in isolates from sewage and seagull faeces (29% and 32% were lower than in isolates from seawater (39%. Seawater AR profiles were similar to those from seagull faeces and differed significantly from sewage AR profiles. Nucleotide sequences matching resistance genes blaTEM, sul1, sul2, tet(A and tet(B, were present in isolates of all sources. Genes conferring resistance to 3rd generation cephalosporins were detected in seawater (blaCTX-M-1 and blaSHV-12 and seagull faeces (blaCMY-2. Plasmid-mediated determinants of resistance to quinolones were found: qnrS1 in all sources and qnrB19 in seawater and seagull faeces. Our results show that seawater is a relevant reservoir of AR and that seagulls are an efficient vehicle to spread human-associated bacteria and resistance genes. The E. coli resistome recaptured from Berlenga coastal water was mainly modulated by seagulls-derived faecal pollution. The repertoire of resistance genes covers antibiotics critically important for humans, a potential risk for human health.

  20. International collaborative study on the occurrence of plasmid-mediated quinolone resistance in Salmonella enterica and Escherichia coli isolated from animals, humans, food and the environment in 13 European countries

    DEFF Research Database (Denmark)

    Veldman, Kees; Cavaco, Lina; Mevius, Dik

    2011-01-01

    containing MIC values for Salmonella and E. coli isolated between 1994 and 2009 in animals, humans, food and the environment from 13 European countries were screened for isolates exhibiting a defined quinolone resistance phenotype, i.e. reduced susceptibility to fluoroquinolones and nalidixic acid. PCR....... In Salmonella, qnrS1 (n = 125) and variants of qnrB (n = 138) were frequently identified, whereas qnrA1 (n = 3) and aac(6')-1b-cr (n = 3) were rarely found. qnrD was detected in 22 Salmonella isolates obtained from humans and animals. In E. coli, qnrS1 was identified in 19 isolates and qnrB19 was found in one...

  1. 尿路分离大肠埃希菌耐药性及喹诺酮类药物耐药株危险因素病例对照研究%The drug resistance of Escherichia coli isolated from urinary tract infection and risk factors of quinolone resistance strains

    Institute of Scientific and Technical Information of China (English)

    张昭勇; 张吉才; 杜毅

    2013-01-01

    Objective To analyze the drug resistance of Escherichia coli isolated from urinary tract infection and risk factors of quinolone resistance strains.Methods A total of 705 cases (strains) with Escherichia coli drug resistance isolated from urine specimens were divided into quinolone sensitive group [474 cases(strains)] and quinolone resistance group [231 cases(strains)].The risk factors of the quinolone resistance strains were analyzed.Results The sensitivity rate of amoxicillin/clavulanic acid,cefalotin,ceftazidime,aztreonam,piperacillin,amikacin,compound sulfamethoxazole,ciprofloxacin,gentamicin,levofloxacin,cefepime in quinolone resistance group was higher than that in quinolone sensitive group [50.2%(238/474) vs.78.8%(182/231),11.6%(55/474) vs.48.5%(112/231),17.9%(85/474) vs.63.2%(146/231),15.0%(71/474) vs.57.6%(133/231),3.2%(15/474) vs.27.7%(64/231),80.8%(383/474)vs.93.1%(215/231),16.0%(76/474) vs.49.8%(115/231),0 vs.100.0%(231/231),32.5% (154/474)vs.70.6% (163/231),3.8% (18/474) vs.98.7% (228/231),18.6% (88/474) vs.63.2% (146/231),P <0.05].Logistic regression analysis showed history of using the third generation cephalosporins and quinolones,urinary drainage and bacterium producing extra-broad spectrum beta-lactamase was independent risk factor for quinolone resistance Escherichia coli (P < 0.05).Conclusions The epidemic of quinolone resistance Escherichia coli isolated from urine specimens is extremely serious.The quinolone resistance is strong,and infection patients have a high medical cost and average length of stay.The quinolone resistance Escherichia coli infection has multiple independent risk factors.To strengthen the control of the independent risk factors can effectively prevent quinolone resistance strains infection spread.%目的 分析尿路感染大肠埃希菌耐药性及喹诺酮类药物耐药株感染危险因素.方法 监测705例(株)尿路感染大肠埃希菌的耐

  2. Characterization of carbapenemases, extended spectrum β-lactamases, quinolone resistance and aminoglycoside resistance determinants in carbapenem-non-susceptible Escherichia coli from a teaching hospital in Chongqing, Southwest China.

    Science.gov (United States)

    Zhang, Chuanming; Xu, Xiuyu; Pu, Shuli; Huang, Shifeng; Sun, Jide; Yang, Shuangshuang; Zhang, Liping

    2014-10-01

    Carbapenem-resistant Escherichiacoli isolates harboring carbapenemases or combining an extended-spectrum β-lactamase (ESBL) enzyme with loss of porins present an increasingly urgent clinical danger. Combined resistance to aminoglycosides and fluoroquinolones in carbapeneme non-susceptible (CNS) isolates will inevitably create problems. In the current study, we characterized the carbapenemases and ESBLs, and the prevalence of quinolone resistance determinants and aminoglycoside resistance determinants in carbapenem-non-susceptible (CNS) E.coli isolates from a teaching hospital in Chongqing, Southwest China in 2012. Thirty non-duplicated CNS E.coli isolates were screened via antimicrobial susceptibility testing, and the drug resistance profiles of the 30 strains were analyzed. Carbapenemase genes blaKPC-2, ESBL genes including blaCTX-M-3, blaCTX-M-14, blaCTX-M-55 and blaTEM, ARD genes including aac(6')-Ib, armA and rmtB, and QRD genes including qnrA, qnrB, qnrC, qnrD, qnrS and aac(6')-Ib-cr were identified and clonal relatedness was investigated by pulsed-field gel electrophoresis. Of the 30 isolates, 2 (6.7%) harbored carbapenemase gene blaKPC-2; 29 (96.7%) carried ESBLs; 20 (66.7%) were QRD positive; and 11 (36.7%) were ARD positive. Between the two blaKPC-2 positive strains, one contained ESBL, QRD and ARD genes, while the other expressed ESBL genes but was negative for both QRD and ARD genes. Of the 29 ESBLs positive isolates, 2 (6.9%) were carbapenemase positive, 19 (65.5%) were QRD positive, and 11 (37.9%) were ARD positive. PFGE revealed genetic diversity among the 30 isolates, indicating that the high prevalence of CNS E. coli isolates was not caused by clonal dissemination. Production of ESBLs was associated with the carbapenem resistance and QRD genes were highly prevalent among the CNS E. coli isolates. Multiple resistant genes were co-expressed in the same isolates. This is the first report of a multidrug resistant carbapenem-non-susceptible E.coli co

  3. Evaluation of quinolones for use in detection of determinants of acquired quinolone resistance, including the new transmissible resistance mechanisms qnrA, qnrB, qnrS, and aac(6')Ib-cr, in Escherichia coli and Salmonella enterica and determinations of wild-type distributions.

    Science.gov (United States)

    Cavaco, L M; Aarestrup, F M

    2009-09-01

    Fluoroquinolone resistance in members of the Enterobacteriaceae family is mostly due to mutations in the quinolone resistance-determining regions of the topoisomerase genes. However, transferable genes encoding quinolone resistance have recently been described. The current methods for susceptibility testing are not adapted to the detection of new resistance determinants, which confer low levels of resistance. The aim of this study was to compare the ability of the screening of the different quinolones by disk diffusion assays and MIC determinations to detect fluoroquinolone resistance. Sixty-nine Escherichia coli strains and 62 Salmonella strains, including strains fully susceptible to quinolones, nalidixic acid-resistant strains, strains with resistance to fluoroquinolones (resistant to nalidixic acid), and strains showing low-level resistance to fluoroquinolones conferred by transferable quinolone resistance genes, including qnrA, qnrB, qnrS, and aac(6')Ib-cr, were selected. Disk diffusion assays and MIC determinations by the agar dilution method were performed, according to CLSI standards, with nalidixic acid, flumequine, oxolinic acid, ciprofloxacin, enrofloxacin, marbofloxacin, norfloxacin, ofloxacin, and levofloxacin. The MIC of levofloxacin was determined by an Etest. The results showed a trimodal distribution of the MICs for both E. coli and Salmonella. The MIC distributions for the isolates varied with the compounds tested. Screening for nalidixic acid resistance by MIC testing or disk diffusion assay was not efficient for the detection of some of the isolates carrying qnr and aac(6')Ib-cr. Transferable resistance genes would best be detected by testing for the MIC of ciprofloxacin or norfloxacin, as testing for the MICs of the other compounds would fail to detect isolates carrying aac(6')Ib-cr because the enzyme produced is able to reduce the activities of these two compounds only due to their chemical structures. In conclusion, screening with nalidixic

  4. A spatial approach for the epidemiology of antibiotic use and resistance in community-based studies: the emergence of urban clusters of Escherichia coli quinolone resistance in Sao Paulo, Brasil

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    Bailey Trevor C

    2011-02-01

    Full Text Available Abstract Background Population antimicrobial use may influence resistance emergence. Resistance is an ecological phenomenon due to potential transmissibility. We investigated spatial and temporal patterns of ciprofloxacin (CIP population consumption related to E. coli resistance emergence and dissemination in a major Brazilian city. A total of 4,372 urinary tract infection E. coli cases, with 723 CIP resistant, were identified in 2002 from two outpatient centres. Cases were address geocoded in a digital map. Raw CIP consumption data was transformed into usage density in DDDs by CIP selling points influence zones determination. A stochastic model coupled with a Geographical Information System was applied for relating resistance and usage density and for detecting city areas of high/low resistance risk. Results E. coli CIP resistant cluster emergence was detected and significantly related to usage density at a level of 5 to 9 CIP DDDs. There were clustered hot-spots and a significant global spatial variation in the residual resistance risk after allowing for usage density. Conclusions There were clustered hot-spots and a significant global spatial variation in the residual resistance risk after allowing for usage density. The usage density of 5-9 CIP DDDs per 1,000 inhabitants within the same influence zone was the resistance triggering level. This level led to E. coli resistance clustering, proving that individual resistance emergence and dissemination was affected by antimicrobial population consumption.

  5. Identification of the main quinolone resistance determinant in Campylobacter jejuni and Campylobacter coli by MAMA-DEG PCR.

    Science.gov (United States)

    Hormeño, Lorena; Palomo, Gonzalo; Ugarte-Ruiz, María; Porrero, M Concepción; Borge, Carmen; Vadillo, Santiago; Píriz, Segundo; Domínguez, Lucas; Campos, Maria J; Quesada, Alberto

    2016-03-01

    Among zoonotic diseases, campylobacteriosis stands out as the major bacterial infection producing human gastroenteritis. Antimicrobial therapy, only recommended in critical cases, is challenged by resistance mechanisms that should be unambiguously detected for achievement of effective treatments. Quinolone (ciprofloxacin) resistance of Campylobacter jejuni and Campylobacter coli, the 2 main Campylobacter detected in humans, is conferred by the mutation gyrA C-257-T, which can be genotyped by several methods that require a previous identification of the pathogen species to circumvent the sequence polymorphism of the gene. A multiplex PCR, based on degenerated oligonucleotides, has been designed for unambiguous identification of the quinolone resistance determinant in Campylobacter spp. isolates. The method was verified with 249 Campylobacter strains isolated from humans (141 isolates) and from the 3 most important animal sources for this zoonosis: poultry (34 isolates), swine (38 isolates), and cattle (36 isolates). High resistance to ciprofloxacin, MIC above 4μg/mL, linked to the mutated genotype predicted by MAMA-DEG PCR (mismatch amplification mutation assay PCR with degenerated primers) was found frequently among isolates from the different hosts.

  6. [Surveillance of Antimicrobial Resistant Esherichia coli by Rectal Swab Method--Annual Change of Prevalence of Quinolone-resistant and ESBL Producing Strains from 2009 to 2013].

    Science.gov (United States)

    Nasu, Yoshitsugu; Sako, Shinichi; Yano, Tomofumi; Kosaka, Noriko

    2015-09-01

    Although most of commonly used antimicrobial agents had been susceptible to Esherichia coli, recently there are a lot of reports concerning about community-acquired infection caused by resistant E. coli. The aim of this study is to define the prevalence of resistant E. coli in normal flora colonization by the rectal swab method. From June 2009 to December 2013, 251 male patients (50-85 year-old, median 68) planned to transrectal prostate biopsy participated in this study. Stools stuck on the glove at the digital examination were provided for culture specimen. Identification of E. coli and determination of MIC was performed by MicroScan WalkAway40plus (Siemens). Isolated E. coli were deemed quinolone-resistant strains when their MIC of levofloxacine was 4 μg/mL or above according to the breakpoint MIC by the CLSI criteria. ESBL producing ability was determined by the double disk method used by CVA contained ESBL definition disc (Eikenkagaku). Of the 251 study patients, 224 patients had positive cultures of E. coli. Twenty-four patients had quinolone-resistant strains and 9 patients had ESBL producing strains. The prevalence of quinolone-resistant strains in 2009, 2010, 2011, 2012 and 2013 were 5.9% (2 out of 34 strains), 13.5% (5 out of 37 strains), 12.5% (4 out of 32 strains), 9.0% (6 out of 67) and 13.0% (7 out of 54 strains), respectively. The prevalence of ESBL producing strains in 2009, 2010, 2011, 2012 and 2013 were 0% (0 out of 34 strains), 5.4% (2 out of 37 strains), 3.1% (1 out of 32 strains), 3.0% (2 out of 67 strains) and 7.4% (4 out of 54 strains), respectively. In 2013, the prevalence of antimicrobial resistant E. coli, both quinolone-resistant and ESBL producing strains, were increasing. We have to pay a close attention to the increase of resistant E. coli.

  7. Niveles de resistencia a quinolonas y otros antimicrobianos en cepas de Escherichia coli comensales en niños de la zona periurbana de Lima, Perú Levels of quinolones resistance and other antimicrobial in non-pathogenic Escherichia coli strains in children from the periurban area of Lima, Peru

    Directory of Open Access Journals (Sweden)

    María J. Pons

    2012-03-01

    Full Text Available El objetivo principal del estudio fue establecer el nivel de resistencia a antimicrobianos en un total de 222 cepas comensales de E. coli de origen fecal, en Perú. Las frecuencias de resistencia encontrados, frente los antimicrobianos evaluados, fueron: ampicilina (62,6%, cotrimoxazol (48,6%, tetraciclina (43,0% y cloranfenicol (15,8%. Destacan los elevados niveles de resistencia a quinolonas: 32% al ácido nalidíxico (NAL y 12% a ciprofloxacino (CIP. Estos elevados niveles hacia las quinolonas en cepas comensales aisladas en niños de esta franja de edad, realzan el uso extendido y el impacto de consumo de este tipo de antimicrobianos en la comunidad, mostrando el riesgo potencial de su pérdida de utilidad en el área.The main aim of this study was to establish the resistance levels to antimicrobial agents, in 222 non-pathogenic E. coli strains of fecal origin in Peru. The proportion of resistance found to the evaluated antimicrobials was ampicillin (62.6%, cotrimoxazole (48,6%, tetracycline (43,0% and chloramphenicol (15,8%. We emphasize the high resistance levels found for quinolones: 32% for nalidixic acid (NAL and 12% for ciprofloxacin (CIP. These high levels of quinoloneresistance in non-pathogenic strains isolated from children in this age group highlight the extensive use and the impact of the intake of this kind of antimicrobials in the community, showing the potential risk of the loss of their utility in the area.

  8. Mechanisms of Reduced Susceptibility to Ciprofloxacin in Escherichia coli Isolates from Canadian Hospitals

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    Patricia J Baudry-Simner

    2012-01-01

    Full Text Available OBJECTIVE: To determine whether plasmid-mediated quinolone resistance (PMQR determinants play a role in the increasing resistance to fluoroquinolones among Escherichia coli isolates in Canadian hospitals, and to determine the mechanisms of reduced susceptibility to ciprofloxacin in a recent collection of 190 clinical E coli isolates.

  9. Plasmid mediated quinolone resistance in Enterobacteriaceae

    NARCIS (Netherlands)

    Veldman, K.T.; LS Klinisch Onderzoek Wagenaar

    2014-01-01

    This thesis describes the occurrence of Plasmid Mediated Quinolone Resistance (PMQR) in Salmonella and E. coli from The Netherlands and other European countries. Furthermore, the genetic background of these genes was characterized. Fluoroquinolones are widely used antibiotics in both human and

  10. Plasmid mediated quinolone resistance in Enterobacteriaceae

    NARCIS (Netherlands)

    Veldman, K.T.; LS Klinisch Onderzoek Wagenaar

    2014-01-01

    This thesis describes the occurrence of Plasmid Mediated Quinolone Resistance (PMQR) in Salmonella and E. coli from The Netherlands and other European countries. Furthermore, the genetic background of these genes was characterized. Fluoroquinolones are widely used antibiotics in both human and veter

  11. Plasmid mediated quinolone resistance in Enterobacteriaceae

    NARCIS (Netherlands)

    Veldman, K.T.; LS Klinisch Onderzoek Wagenaar

    2014-01-01

    This thesis describes the occurrence of Plasmid Mediated Quinolone Resistance (PMQR) in Salmonella and E. coli from The Netherlands and other European countries. Furthermore, the genetic background of these genes was characterized. Fluoroquinolones are widely used antibiotics in both human and veter

  12. Escherichia Coli

    Science.gov (United States)

    Goodsell, David S.

    2009-01-01

    Diverse biological data may be used to create illustrations of molecules in their cellular context. I describe the scientific results that support a recent textbook illustration of an "Escherichia coli cell". The image magnifies a portion of the bacterium at one million times, showing the location and form of individual macromolecules. Results…

  13. Clinical impact of fluoroquinolone-resistant Escherichia coli in the fecal flora of hematological patients with neutropenia and levofloxacin prophylaxis.

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    Yong Chong

    Full Text Available BACKGROUND: Fluoroquinolone prophylaxis in patients with neutropenia and hematological malignancies is said to be effective on febrile netropenia (FN-related infection and mortality; however, the emergence of antibiotic resistance has become a concern. Ciprofloxacin and levofloxacin prophylaxis are most commonly recommended. A significant increase in the rate of quinolone-resistant Escherichia coli in fecal flora has been reported following ciprofloxacin prophylaxis. The acquisition of quinolone-resistant E. coli after levofloxacin use has not been evaluated. METHODS: We prospectively examined the incidence of quinolone-resistant E. coli isolates recovered from stool cultures before and after levofloxacin prophylaxis in patients with neutropenia from August 2011 to May 2013. Some patients received chemotherapy multiple times. RESULTS: In this trial, 68 patients were registered. Levofloxacin-resistant E. coli isolates were detected from 11 and 13 of all patients before and after the prophylaxis, respectively. However, this was not statistically significant (P = 0.65. Multiple prophylaxis for sequential chemotherapy did not induce additional quinolone resistance among E. coli isolates. Interestingly, quinolone-resistant E. coli, most of which were extended-spectrum β-lactamase (ESBL producers, were already detected in approximately 20% of all patients before the initiation of prophylaxis. FN-related bacteremia developed in 2 patients, accompanied by a good prognosis. CONCLUSIONS: Levofloxacin prophylaxis for neutropenia did not result in a significant acquisition of quinolone-resistant E. coli. However, we detected previous colonization of quinolone-resistant E. coli before prophylaxis, which possibly reflects the spread of ESBL. The epidemic spread of resistant E. coli as a local factor may influence strategies toward the use of quinolone prophylaxis.

  14. Prevalence of antimicrobial resistance and integrons in Escherichia Coli from Punjab, Pakistan

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    Idrees Muhammad

    2011-06-01

    Full Text Available Antimicrobial resistance was studied in Escherichia coli strains isolated from urine samples of 457 patients suffering from urinary tract infection. High prevalence of class 1 integrons (43.56%, sulfamethoxazole resistance genes sul1 (45.54% and sul2 (51.48% along with occurrence of quinolone resistance genes was detected in multi drug resistance isolates.

  15. Influência do uso de enrofloxacina no desenvolvimento de resistência às quinolonas mediada por plasmídeos em Escherichia coli de vitelos [Selection of plasmid-mediated quinolone resistance in commensal E. coli by the use of enrofloxacin in calves

    DEFF Research Database (Denmark)

    Guerreiro, L.; Couto, N.; Centeno, M.

    os genes qnr (A, B, C, D e S), o gene aac(6’)-Ib-cr e o genecodificante da de bomba de efluxo qQep A; e ii) determinar a Concentração Inibitória Mínima (CIM) dos antibióticos ácido nalidíxico AN, ciprofloxacina CIP e levofloxacina LEV, em isolados de E. coli de vitelos previamente isolados após...

  16. Molecular Characterization and Antimicrobial Susceptibility Testing of Escherichia coli Isolates from Patients with Urinary Tract Infections in 20 Chinese Hospitals

    DEFF Research Database (Denmark)

    Cao, Xiaoli; Cavaco, Lina; Lv, Yuan

    2011-01-01

    A total of 222 urinary Escherichia coli isolates from 20 tertiary hospitals in 15 different provinces and 4 municipalities in mainland China were characterized by antimicrobial susceptibility, phylogrouping, and the presence of plasmid-mediated quinolone resistance genes. A subset of 138 suspecte...

  17. Quinolone resistance in absence of selective pressure: the experience of a very remote community in the Amazon forest.

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    Lucia Pallecchi

    Full Text Available BACKGROUND: Quinolones are potent broad-spectrum bactericidal agents increasingly employed also in resource-limited countries. Resistance to quinolones is an increasing problem, known to be strongly associated with quinolone exposure. We report on the emergence of quinolone resistance in a very remote community in the Amazon forest, where quinolones have never been used and quinolone resistance was absent in 2002. METHODS: The community exhibited a considerable level of geographical isolation, limited contact with the exterior and minimal antibiotic use (not including quinolones. In December 2009, fecal carriage of antibiotic resistant Escherichia coli was investigated in 120 of the 140 inhabitants, and in 48 animals reared in the community. All fluoroquinolone-resistant isolates were genotyped and characterized for the mechanisms of plasmid- and chromosomal-mediated quinolone resistance. PRINCIPAL FINDINGS: Despite the characteristics of the community remained substantially unchanged during the period 2002-2009, carriage of quinolone-resistant E. coli was found to be common in 2009 both in humans (45% nalidixic acid, 14% ciprofloxacin and animals (54% nalidixic acid, 23% ciprofloxacin. Ciprofloxacin-resistant isolates of human and animal origin showed multidrug resistance phenotypes, a high level of genetic heterogeneity, and a combination of GyrA (Ser83Leu and Asp87Asn and ParC (Ser80Ile substitutions commonly observed in fluoroquinolone-resistant clinical isolates of E. coli. CONCLUSIONS: Remoteness and absence of antibiotic selective pressure did not protect the community from the remarkable emergence of quinolone resistance in E. coli. Introduction of the resistant strains from antibiotic-exposed settings is the most likely source, while persistence and dissemination in the absence of quinolone exposure is likely mostly related with poor sanitation. Interventions aimed at reducing the spreading of resistant isolates (by improving sanitation

  18. Rapid evolution of fluoroquinolone-resistant Escherichia coli in Nigeria is temporally associated with fluoroquinolone use

    Science.gov (United States)

    2011-01-01

    Background Antibiotic resistance has necessitated fluoroquinolone use but little is known about the selective forces and resistance trajectory in malaria-endemic settings, where selection from the antimalarial chloroquine for fluoroquinolone-resistant bacteria has been proposed. Methods Antimicrobial resistance was studied in fecal Escherichia coli isolates in a Nigerian community. Quinolone-resistance determining regions of gyrA and parC were sequenced in nalidixic acid resistant strains and horizontally-transmitted quinolone-resistance genes were sought by PCR. Antimicrobial prescription practices were compared with antimicrobial resistance rates over a period spanning three decades. Results Before 2005, quinolone resistance was limited to low-level nalixidic acid resistance in fewer than 4% of E. coli isolates. In 2005, the proportion of isolates demonstrating low-level quinolone resistance due to elevated efflux increased and high-level quinolone resistance and resistance to the fluoroquinolones appeared. Fluoroquinolone resistance was attributable to single nucleotide polymorphisms in quinolone target genes gyrA and/or parC. By 2009, 35 (34.5%) of isolates were quinolone non-susceptible with nine carrying gyrA and parC SNPs and six bearing identical qnrS1 alleles. The antimalarial chloroquine was heavily used throughout the entire period but E. coli with quinolone-specific resistance mechanisms were only detected in the final half decade, immediately following the introduction of the fluoroquinolone antibacterial ciprofloxacin. Conclusions Fluoroquinolones, and not chloroquine, appear to be the selective force for fluoroquinolone-resistant fecal E. coli in this setting. Rapid evolution to resistance following fluoroquinolone introduction points the need to implement resistant containment strategies when new antibacterials are introduced into resource-poor settings with high infectious disease burdens. PMID:22060770

  19. Impact of mutations in DNA gyrase genes on quinolone resistance in Campylobacter jejuni.

    Science.gov (United States)

    Changkwanyeun, Ruchirada; Yamaguchi, Tomoyuki; Kongsoi, Siriporn; Changkaew, Kanjana; Yokoyama, Kazumasa; Kim, Hyun; Suthienkul, Orasa; Usui, Masaru; Tamura, Yutaka; Nakajima, Chie; Suzuki, Yasuhiko

    2016-10-01

    Amino acid substitutions providing quinolone resistance to Campyloabcter jejuni have been found in the quinolone resistance-determining region of protein DNA gyrase subunit A (GyrA), with the highest frequency at position 86 followed by position 90. In this study, wild-type and mutant recombinant DNA gyrase subunits were expressed in Escherichia coli and purified using Ni-NTA agarose column chromatography. Soluble 97 kDa GyrA and 87 kDa DNA gyrase subunit B were shown to reconstitute ATP-dependent DNA supercoiling activity. A quinolone-inhibited supercoiling assay demonstrated the roles of Thr86Ile, Thr86Ala, Thr86Lys, Asp90Asn, and Asp90Tyr amino acid substitutions in reducing sensitivity to quinolones. The marked effect of Thr86Ile on all examined quinolones suggested the advantage of this substitution in concordance with recurring isolation of quinolone-resistant C. jejuni. An analysis of the structure-activity relationship showed the importance of the substituent at position 8 in quinolones to overcome the effect of Thr86Ile. Sitafloxacin (SIT), which has a fluorinate cyclopropyl ring at R-1 and a chloride substituent at R-8, a characteristic not found in other quinolones, showed the highest inhibitory activity against all mutant C. jejuni gyrases including ciprofloxacin-resistant mutants. The results suggest SIT as a promising drug for the treatment of campylobacteriosis caused by CIP-resistant C. jejuni. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Occurrence of the Plasmid-Mediated Fluoroquinolone Resistance qepA1 Gene in Two Clonal Clinical Isolates of CTX-M-15-Producing Escherichia coli from Algeria.

    Science.gov (United States)

    Yanat, Betitera; Dali Yahia, Radia; Yazi, Leila; Machuca, Jesús; Díaz-De-Alba, Paula; Touati, Abdelaziz; Pascual, Álvaro; Rodríguez-Martínez, José-Manuel

    2016-10-13

    QepA is a plasmid-mediated quinolone resistance determinant of low prevalence described worldwide, mainly in Enterobacteriaceae. This study describes, for the first time in Algeria, two clonally related, QepA-producing Escherichia coli clinical isolates positive for CTX-M-15. The clonal spread of these multidrug-resistant isolates is a major public health concern.

  1. International collaborative study on the occurrence of plasmid mediated quinolone resisitance in Salmonella enterica en Escherichia coli isolated from animals, humans, food and the environment in 13 European countries.

    NARCIS (Netherlands)

    Veldman, K.T.; Cavaco, L.M.; Mevius, D.J.; Battisti, A.; Botteldoorn, N.; Bruneau, M.; Cerny, T.; Franco, A.; Frutos Escobar, De C.; Guerra, B.; Gutierrez, M.; Hopkins, K.; Myllyniemi, A.L.; Perrin-Guyomard, A.; Schroeter, A.; Sunde, M.; Wasyl, D.; Aarestrup, F.M.

    2011-01-01

    Objectives This study was initiated to collect retrospective information on the occurrence of plasmid-mediated quinolone resistance (PMQR) in Salmonella enterica and Escherichia coli isolates in Europe and to identify the responsible genes. Methods Databases of national reference laboratories contai

  2. Characterization of quinolone resistance mechanisms in Enterobacteriaceae recovered from diseased companion animals in Europe.

    Science.gov (United States)

    Guillard, T; de Jong, A; Limelette, A; Lebreil, A L; Madoux, J; de Champs, C

    2016-10-15

    ComPath is a European monitoring programme dedicated to the collection of bacterial pathogens from diseased dogs and cats to determine their antibiotic susceptibility. The objective was to characterize genetic determinants associated with quinolone resistance among 69 enrofloxacin non-wild type strains selected among 604 non-duplicate Enterobacteriaceae isolates collected in 10EU countries from 2008 to 2010: quinolone resistance determining region (QRDR) and plasmid-mediated quinolone resistance (PMQR). Among them, 17% (12/69) carried at least one PMQR (9/12 qnrB, qnrS or qnrD and 4/12 aac(6')-Ib-cr) and 83% (57/69) no PMQR. All the Klebsiella pneumoniae isolates chromosomally carried oqxAB . No qepA genes were detected. Eight strains did not carry any mutations in QRDR (4 PMQR-positive and 4 PMQR-negative strains). From the 12 PMQR-positive strains, 4 showed enrofloxacin MICs≤2μg/mL, and 8 MICs≥8μg/mL (resistant). These latter strains carried 1-5 mutations in QRDR, including a ParE I529L mutation. qnrD was found in 2 Proteus mirabilis and the plasmids were similar to pDIJ09-518a previously described. For the 57 non-PMQR strains, 29 strains showed MICs≤2μg/mL (4 with no QRDR mutations, 21 with 1 mutation in GyrA, 4 with 2 mutations in GyrA) and 28 showed enrofloxacin MICs≥8μg/mL carrying at least 2 mutations in QRDR, including a ParE I529L mutation for 2 Escherichia coli strains with a total of 5 QRDR mutations. No GyrB mutations were found. qnr was the major PMQR and qnrD was only detected in Proteus spp. Twelve strains carried at least 4 mutations.

  3. Impact of the E540V amino acid substitution in GyrB of Mycobacterium tuberculosis on quinolone resistance.

    Science.gov (United States)

    Kim, Hyun; Nakajima, Chie; Yokoyama, Kazumasa; Rahim, Zeaur; Kim, Youn Uck; Oguri, Hiroki; Suzuki, Yasuhiko

    2011-08-01

    Amino acid substitutions conferring resistance to quinolones in Mycobacterium tuberculosis have generally been found within the quinolone resistance-determining regions (QRDRs) in the A subunit of DNA gyrase (GyrA) rather than the B subunit of DNA gyrase (GyrB). To clarify the contribution of an amino acid substitution, E540V, in GyrB to quinolone resistance in M. tuberculosis, we expressed recombinant DNA gyrases in Escherichia coli and characterized them in vitro. Wild-type and GyrB-E540V DNA gyrases were reconstituted in vitro by mixing recombinant GyrA and GyrB. Correlation between the amino acid substitution and quinolone resistance was assessed by the ATP-dependent DNA supercoiling assay, quinolone-inhibited supercoiling assay, and DNA cleavage assay. The 50% inhibitory concentrations of eight quinolones against DNA gyrases bearing the E540V amino acid substitution in GyrB were 2.5- to 36-fold higher than those against the wild-type enzyme. Similarly, the 25% maximum DNA cleavage concentrations were 1.5- to 14-fold higher for the E540V gyrase than for the wild-type enzyme. We further demonstrated that the E540V amino acid substitution influenced the interaction between DNA gyrase and the substituent(s) at R-7, R-8, or both in quinolone structures. This is the first detailed study of the contribution of the E540V amino acid substitution in GyrB to quinolone resistance in M. tuberculosis.

  4. Taxonomy Icon Data: Escherichia coli [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Escherichia coli Escherichia coli Escherichia_coli_L.png Escherichia_coli_NL.png Escherich...ia_coli_S.png Escherichia_coli_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Escherichia+co...li&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Escherichia+coli&t=NL http://biosciencedbc.jp/taxono...my_icon/icon.cgi?i=Escherichia+coli&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Escherichia+coli&t=NS ...

  5. Conjugation between quinolone-susceptible bacteria can generate mutations in the quinolone resistance-determining region, inducing quinolone resistance.

    Science.gov (United States)

    Pitondo-Silva, André; Martins, Vinicius Vicente; Silva, Carolina Fávero da; Stehling, Eliana Guedes

    2015-02-01

    Quinolones are an important group of antibacterial agents that can inhibit DNA gyrase and topoisomerase IV activity. DNA gyrase is responsible for maintaining bacteria in a negatively supercoiled state, being composed of subunits A and B. Topoisomerase IV is a homologue of DNA gyrase and consists of two subunits codified by the parC and parE genes. Mutations in gyrA and gyrB of DNA gyrase may confer resistance to quinolones, and the majority of resistant strains show mutations between positions 67 and 106 of gyrA, a region denoted the quinolone resistance-determining region (QRDR). The most frequent substitutions occur at positions 83 and 87, but little is known about the mechanisms promoting appearance of mutations in the QRDR. The present study proposes that some mutations in the QRDR could be generated as a result of the natural mechanism of conjugation between bacteria in their natural habitat. This event was observed following conjugation in vitro of two different isolates of quinolone-susceptible Pseudomonas aeruginosa, which transferred plasmids of different molecular weights to a recipient strain of Escherichia coli (HB101), also quinolone-susceptible, generating two different transconjugants that presented mutations in DNA gyrase and acquisition of resistance to all quinolones tested.

  6. PATHOGENIC ESCHERICHIA COLI

    Science.gov (United States)

    Escherichia coli is a bacterial species which inhabits the gastrointestinal tract of man and warm-blooded animals. Because of the ubiquity of this bacterium in the intestinal flora, it serves as an important indicator organism of fecal contamination. E. coli, aside from serving a...

  7. Fluoroquinolone-resistance mechanisms and phylogenetic background of clinical Escherichia coli strains isolated in south-east Poland.

    Science.gov (United States)

    Korona-Glowniak, Izabela; Skrzypek, Kinga; Siwiec, Radosław; Wrobel, Andrzej; Malm, Anna

    2016-07-01

    Fluorochinolones are a class of broad-spectrum antimicrobials in the treatment of several infections, including those caused by Escherichia coli. Due to the increasing resistance of bacteria to antimicrobials, an understanding of fluoroquinolone resistance is important for infection control. The aim of this study was to determine susceptibility of clinical E. coli strains to fluoroquinolones and characterize their mechanisms of quinolone resistance. Totally, 79 non-duplicate clinical E. coli isolates included in this study were mainly from skin lesion -36 (45.6%) isolates; 54 (68.4%) isolates were assigned to phylogenetic B2 group. Resistance to ciprofloxacin was found in 20 isolates. In the quinolone resistance-determining region (QRDR) region of gyrA and parC, 4 types of point mutations were detected. Mutations in parC gene were found in all strains with gyrA mutations. Predominance of double mutation in codon 83 and 87 of gyrA (90%) and in codon 80 of parC (90%) was found. Moreover, plasmid-mediated quinolone resistance (PMRQ) determinants (qnrA or qnrB and/or aac(6')-Ib-cr) were present in 5 (25%) out of 20 fluoroquinolone-resistant isolates. Resistance to fluoroquinolones in all of the tested clinical E. coli isolates correlated with point mutations in both gyrA and parC. The majority of fluoroquinolone-resistant strains belonged to D and B2 phylogenetic groups.

  8. Virulence factors profiles and ESBL production in Escherichia coli causing bacteremia in Peruvian children.

    Science.gov (United States)

    Palma, Noemí; Gomes, Cláudia; Riveros, Maribel; García, Wilfredo; Martínez-Puchol, Sandra; Ruiz-Roldán, Lidia; Mateu, Judit; García, Coralith; Jacobs, Jan; Ochoa, Theresa J; Ruiz, Joaquim

    2016-09-01

    The presence of 25 virulence genes (VGs), genetic phylogroups, quinolone-resistance and Extended Spectrum β-lactamase (ESBL)-production was assessed in 65 Escherichia coli isolates from blood cultures in children <5 years in Peru. The most frequent VGs were fimA (89.2%), iutA (83.1%), agn43 (72.3%), iucA (67.7%), and fyuA (49.2%). The isolates belonged to D (47.7%), A (26.1%), B1 (21.5%), and B2 (4.6%) phylogroups. D + B2 isolates presented a high number of fimA, hly, papC, sat, and fyuA genes. Quinolone-susceptible (22 isolates - 33.8%) and ESBL-negative (31 isolates - 47.7%) isolates carried more VGs that their respective counterparts (5.7 vs. 4.7 and 5.3 vs. 4.4 respectively); the frequency of the fyuA, aat, aap, and hly genes significantly differed between quinolone-resistant and quinolone-susceptible isolates. Neonatal sepsis isolates tended to be more quinolone-resistant (P = 0.0697) and ESBL-producers (P = 0.0776). Early-onset neonatal sepsis isolates possessed a high number of VGs (5.2 VGs), especially in neonates of ≤1 day (5.9 VGs).

  9. Quinolone resistance: much more than predicted

    Directory of Open Access Journals (Sweden)

    Alvaro eHernandez

    2011-02-01

    Full Text Available Since quinolones are synthetic antibiotics, it was predicted that mutations in target genes would be the only mechanism through which resistance could be acquired, because there will not be quinolone resistance genes in nature. Contrary to this prediction, a variety of elements ranging from efflux pumps, target-protecting proteins and even quinolone-modifying enzymes have been shown to contribute to quinolone resistance. The finding of some of these elements in plasmids indicates that quinolone resistance can be transferable. As a result, there has been a developing interest on the reservoirs for quinolone resistance genes and on the potential risks associated with the use of these antibiotics in non-clinical environments. As a matter of fact, plasmid-encoded, quinolone-resistance qnr genes originated in the chromosome of aquatic bacteria, thus the use of quinolones in fish farming might constitute a risk for the emergence of resistance. Failure to predict the development of quinolone resistance reinforces the need of taking into consideration the wide plasticity of biological systems for future predictions. This plasticity allows pathogens to deal with toxic compounds, including those with a synthetic origin as quinolones.

  10. Diarrheagenic Escherichia coli.

    Science.gov (United States)

    Gomes, Tânia A T; Elias, Waldir P; Scaletsky, Isabel C A; Guth, Beatriz E C; Rodrigues, Juliana F; Piazza, Roxane M F; Ferreira, Luís C S; Martinez, Marina B

    2016-12-01

    Most Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in healthy and immunocompromised individuals. Diarrheal illnesses are a severe public health problem and a major cause of morbidity and mortality in infants and young children, especially in developing countries. E. coli strains that cause diarrhea have evolved by acquiring, through horizontal gene transfer, a particular set of characteristics that have successfully persisted in the host. According to the group of virulence determinants acquired, specific combinations were formed determining the currently known E. coli pathotypes, which are collectively known as diarrheagenic E. coli. In this review, we have gathered information on current definitions, serotypes, lineages, virulence mechanisms, epidemiology, and diagnosis of the major diarrheagenic E. coli pathotypes.

  11. Characterization of CTX-M enzymes, quinolone resistance determinants, and antimicrobial residues from hospital sewage, wastewater treatment plant, and river water.

    Science.gov (United States)

    Conte, Danieli; Palmeiro, Jussara Kasuko; da Silva Nogueira, Keite; de Lima, Thiago Marenda Rosa; Cardoso, Marco André; Pontarolo, Roberto; Degaut Pontes, Flávia Lada; Dalla-Costa, Libera Maria

    2017-02-01

    Multidrug-resistant (MDR) bacteria are widespread in hospitals and have been increasingly isolated from aquatic environments. The aim of the present study was to characterize extended-spectrum β-lactamase (ESBL) and quinolone-resistant Enterobacteriaceae from a hospital effluent, sanitary effluent, inflow sewage, aeration tank, and outflow sewage within a wastewater treatment plant (WWTP), as well as river water upstream and downstream (URW and DRW, respectively), of the point where the WWTP treated effluent was discharged. β-lactamase (bla) genes, plasmid-mediated quinolone resistance (PMQR), and quinolone resistance-determining regions (QRDRs) were assessed by amplification and sequencing in 55 ESBL-positive and/or quinolone-resistant isolates. Ciprofloxacin residue was evaluated by high performance liquid chromatography. ESBL-producing isolates were identified in both raw (n=29) and treated (n=26) water; they included Escherichia coli (32), Klebsiella pneumoniae (22) and Klebsiella oxytoca (1). Resistance to both cephalosporins and quinolone was observed in 34.4% of E. coli and 27.3% of K. pneumoniae. Resistance to carbapenems was found in 5.4% of K. pneumoniae and in K. oxytoca. Results indicate the presence of blaCTX-M (51/55, 92.7%) and blaSHV (8/55, 14.5%) ESBLs, and blaGES (2/55, 3.6%) carbapenemase-encoding resistance determinants. Genes conferring quinolone resistance were detected at all sites, except in the inflow sewage and aeration tanks. Quinolone resistance was primarily attributed to amino acid substitutions in the QRDR of GyrA (47%) or to the presence of PMQR (aac-(6')-Ib-cr, oqxAB, qnrS, and/or qnrB; 52.9%) determinants. Ciprofloxacin residue was absent only from URW. Our results have shown strains carrying ESBL genes, PMQR determinants, and mutations in the gyrA QRDR genes mainly in hospital effluent, URW, and DRW samples. Antimicrobial use, and the inefficient removal of MDR bacteria and antibiotic residue during sewage treatment, may

  12. Characterization of Plasmid-Mediated Quinolone Resistance Determinants in High-Level Quinolone-Resistant Enterobacteriaceae Isolates from the Community: First Report of qnrD Gene in Algeria.

    Science.gov (United States)

    Yanat, Betitera; Machuca, Jesús; Díaz-De-Alba, Paula; Mezhoud, Halima; Touati, Abdelaziz; Pascual, Álvaro; Rodríguez-Martínez, José-Manuel

    2017-01-01

    The objective was to assess the prevalence of plasmid-mediated quinolone resistance (PMQR)-producing isolates in a collection of quinolone-resistant Enterobacteriaceae of community origin isolated in Bejaia, Algeria. A total of 141 nalidixic acid-resistant Enterobacteriaceae community isolates were collected in Bejaia (Northern Algeria) and screened for PMQR genes using polymerase chain reaction (PCR). For PMQR-positive strains, antimicrobial susceptibility testing was performed by broth microdilution and disk diffusion. Mutations in the quinolone resistance-determining regions of the target genes, gyrA and parC, were detected with a PCR-based method and sequencing. Southern blotting, conjugation and transformation assays and molecular typing by pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing were also performed. The prevalence of PMQR-producing Enterobacteriaceae isolates was 13.5% (19/141); 11 of these isolates produced Aac(6')-Ib-cr and 8 were qnr-positive (4 qnrB1-like, 2 qnrS1-like, and 2 qnrD1-like), including the association with aac(6')-Ib-cr gene in three cases. PMQR gene transfer by conjugation was successful in 6 of 19 isolates tested. PFGE revealed that most of the PMQR-positive Escherichia coli isolates were unrelated, except for two groups comprising two and four isolates, respectively, including the virulent multidrug-resistant clone E. coli ST131 that were clonally related. Our findings indicate that PMQR determinants are prevalent in Enterobacteriaceae isolates from the community studied. We describe the first report of the qnrD gene in Algeria.

  13. Zoonotic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Wasteson Yngvild

    2002-03-01

    Full Text Available Escherichia coli is a normal inhabitant of the gastrointestinal tract of all warm-blooded animals, but variants of this species is also among the important etiological agents of enteritis and several extraintestinal diseases. The E. coli strains that cause diarrhoeal illness are categorised into pathogenicity groups based on virulence properties, mechanisms of pathogenicity, clinical symptoms and serology. The five main categories include enterotoxinogenic E. coli (ETEC, enteropathogenic E. coli (EPEC, enteroaggregative E. coli (EAggEC, enteroinvasive E. coli (EIEC and Shiga (Vero toxin-producing E. coli (STEC/VTEC. From a zoonotic point of view, STEC is the only E. coli pathogenicity group of major interest, as the shiga toxin-producing strains are able to cause severe disease in humans when being transmitted through the food chain from their animal reservoirs. The focus of this manuscript is therefore on STEC; pathogenicity factors, disease, the reservoirs and on-farm ecology, transmission into the food chain, growth and survival in food and in the environment, and the shiga toxin-encoding bacteriophages.

  14. Detection of plasmid-mediated IMP-1 metallo-β-lactamase and quinolone resistance determinants in an ertapenem-resistant Enterobacter cloacae isolate

    Institute of Scientific and Technical Information of China (English)

    Li-rong CHEN; Hong-wei ZHOU; Jia-chang CAI; Rong ZHANG; Gong-xiang CHEN

    2009-01-01

    Objective: To investigate the mechanism of carbapenem resistance and the occurrence of plasmid-mediated quinolone resistance determinants qnr and aac(6')-Ib-cr in a clinical isolate of Enterobacter cloacae. Methods: An ertapenem-resistant E. cloacae ZY106, which was isolated from liquor puris of a female gastric cancer patient in a Chinese hospital, was investigated. Antibiotic susceptibilities were determined by agar dilution method. Conjugation experiments, isoelectric focusing, polymerase chain reaction (PCR), and DNA sequence analyses of plasmid-mediated carbapenemases and quinolone resistance determinants were preformed to confirm the genotype. Outer membrane proteins (OMPs) were examined by urea-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Urea-SDS-PAGE). Results: Minimum inhibitory concentrations (MCs) of imipenem, mer-openem, and ertapenem for ZY106 were 2,4, and 16 ug/ml, respectively. Conjugation studies with Escherichia coli resulted in the transfer of significantly reduced carbapenem susceptibility. ZY106 produced IMP-1 metallo-p-lactamase and CTX-M-3 extended-spectrum P-lactamase, and E. coli transconjugant produced IMP-1. Plasmid-mediated quinolone resistance determinant qnrSI was detected in ZY106. Transfer of the qnrSI-encoding-plasmid into E. coli by conjugation resulted in intermediate resistance to ciprofloxacin in E. coli transconjugant. Urea-SDS-PAGE analysis of OMPs showed that ZY106 lacked an OMP of approximately 38 KDa. Conclusion: It is the first IMP-1-producing Enterobacteriaceae in China and the first report of a clinical isolate that harbors both blaIMP and qnrS genes as well. The blaIMP-1, blaCTX-M-3, and qnrSl are encoded at three different plasmids. IMP-1 combined with the loss of an OMP possibly resulted in ertapenem resistance and reduced imipenem and mero-penem susceptibility in E. cloacae.

  15. PART I. ESCHERICHIA COLI

    Directory of Open Access Journals (Sweden)

    Sanaa Mahdi Oraibi

    2016-11-01

    Full Text Available The presence of Escherichia coli in the air of facilities involved in management and composting of post-slaughter poultry wastes in selected plants of West Western Pomerania region was studied. Measurements were made on four dates in a variety of weather conditions during the year. The study was conducted at 5 objects that differ in the type of waste and the degree of preparation for composting. These were: chemical treatment and preliminary processing plant, liquid wastes reservoir, platform for preparation of materials for composting, storage of biological sediments, and composting facility. Measurement of bacteria count was carried out in accordance with the applicable procedures on selective chromogenic TBX medium. The assays revealed the presence of E. coli at all test objects, but not always on all measurement dates. It has been shown that the presence of E. coli was from 20 to 3047 CFU∙m-3 of air, although the largest quantities were most frequently detected in the air of the building for post-slaughter waste pre-treatment in chemical treatment plant.

  16. Temporal interplay between efflux pumps and target mutations in development of antibiotic resistance in Escherichia coli.

    Science.gov (United States)

    Singh, Renu; Swick, Michelle C; Ledesma, Kimberly R; Yang, Zhen; Hu, Ming; Zechiedrich, Lynn; Tam, Vincent H

    2012-04-01

    The emergence of resistance presents a debilitating change in the management of infectious diseases. Currently, the temporal relationship and interplay between various mechanisms of drug resistance are not well understood. A thorough understanding of the resistance development process is needed to facilitate rational design of countermeasure strategies. Using an in vitro hollow-fiber infection model that simulates human drug treatment, we examined the appearance of efflux pump (acrAB) overexpression and target topoisomerase gene (gyrA and parC) mutations over time in the emergence of quinolone resistance in Escherichia coli. Drug-resistant isolates recovered early (24 h) had 2- to 8-fold elevation in the MIC due to acrAB overexpression, but no point mutations were noted. In contrast, high-level (≥ 64× MIC) resistant isolates with target site mutations (gyrA S83L with or without parC E84K) were selected more readily after 120 h, and regression of acrAB overexpression was observed at 240 h. Using a similar dosing selection pressure, the emergence of levofloxacin resistance was delayed in a strain with acrAB deleted compared to the isogenic parent. The role of efflux pumps in bacterial resistance development may have been underappreciated. Our data revealed the interplay between two mechanisms of quinolone resistance and provided a new mechanistic framework in the development of high-level resistance. Early low-level levofloxacin resistance conferred by acrAB overexpression preceded and facilitated high-level resistance development mediated by target site mutation(s). If this interpretation is correct, then these findings represent a paradigm shift in the way quinolone resistance is thought to develop.

  17. Temporal Interplay between Efflux Pumps and Target Mutations in Development of Antibiotic Resistance in Escherichia coli

    Science.gov (United States)

    Singh, Renu; Swick, Michelle C.; Ledesma, Kimberly R.; Yang, Zhen; Hu, Ming; Zechiedrich, Lynn

    2012-01-01

    The emergence of resistance presents a debilitating change in the management of infectious diseases. Currently, the temporal relationship and interplay between various mechanisms of drug resistance are not well understood. A thorough understanding of the resistance development process is needed to facilitate rational design of countermeasure strategies. Using an in vitro hollow-fiber infection model that simulates human drug treatment, we examined the appearance of efflux pump (acrAB) overexpression and target topoisomerase gene (gyrA and parC) mutations over time in the emergence of quinolone resistance in Escherichia coli. Drug-resistant isolates recovered early (24 h) had 2- to 8-fold elevation in the MIC due to acrAB overexpression, but no point mutations were noted. In contrast, high-level (≥64× MIC) resistant isolates with target site mutations (gyrA S83L with or without parC E84K) were selected more readily after 120 h, and regression of acrAB overexpression was observed at 240 h. Using a similar dosing selection pressure, the emergence of levofloxacin resistance was delayed in a strain with acrAB deleted compared to the isogenic parent. The role of efflux pumps in bacterial resistance development may have been underappreciated. Our data revealed the interplay between two mechanisms of quinolone resistance and provided a new mechanistic framework in the development of high-level resistance. Early low-level levofloxacin resistance conferred by acrAB overexpression preceded and facilitated high-level resistance development mediated by target site mutation(s). If this interpretation is correct, then these findings represent a paradigm shift in the way quinolone resistance is thought to develop. PMID:22232279

  18. Escherichia coli Uropathogenesis In Vitro

    DEFF Research Database (Denmark)

    Andersen, Thomas E; Khandige, Surabhi; Madelung, Michelle

    2012-01-01

    Uropathogenic Escherichia coli (UPEC) strains are capable of invading bladder epithelial cells (BECs) on the bladder luminal surface. Based primarily on studies in mouse models, invasion is proposed to trigger an intracellular uropathogenic cascade involving intracellular bacterial proliferation...

  19. Plasmid-mediated quinolone resistance among extended spectrum beta lactase producing Enterobacteriaceae from bloodstream infections.

    Science.gov (United States)

    Domokos, Judit; Kristóf, Katalin; Szabó, Dóra

    2016-09-01

    The purpose of this study was to determine prevalence and molecular characterization of plasmid-mediated quinolone resistance (PMQR) genes [qnrA, qnrB, qnrC, qnrD, qnrS, aac(6')-Ib-cr, qepA, and oqxAB] among extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella spp. isolates from bloodcultures in Hungary. A total of 103 isolates were tested for quinolone susceptibility by microdilution method and PMQR genes were detected by polymerase chain reaction. About 40 ESBL-producing E. coli (39%) and 50 ESBL-producing Klebsiella spp. strains (48%) were resistant to ciprofloxacin; 40 ESBL-producing E. coli (39%) and 47 ESBL-producing Klebsiella spp. strains (45%) were resistant to levofloxacin; and 88 strains including 40 ESBL-producing E. coli (39%) and 48 (47%) ESBL-producing Klebsiella spp. were resistant to moxifloxacin. Among the 103 ESBL-producing isolates, 77 (75%) isolates (30 E. coli and 47 Klebsiella spp.) harbored PMQR genes. The most commonly detected gene was aac(6')-Ib-cr (65%). The occurrence of qnrS gene was 6%. Interestingly, qnrA, qnrB, qnrC, qnrD, and qepA were not found in any isolates. Among 77 PMQR-positive isolates, 27 (35.1%) and 1 (1.3%) carried two and three different PMQR genes, respectively. Only Klebsiella spp. harbored more than one PMQR genes. Observing prevalence of PMQR genes in the last 8 years, the increasing incidence of aac(6')-Ib-cr and oqxAB can be seen. Our results highlight high frequency of PMQR genes among ESBL-producing Klebsiella pneumoniae and E. coli isolates with an increasing dynamics in Hungary.

  20. Asymptomatic bacteriuria Escherichia coli strains

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Nielsen, E.M.; Klemm, Per

    2006-01-01

    Urinary tract infections (UTIs) affect millions of people each year. Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU) in humans. Persons affected by ABU may carry a particular E. coli strain for extended periods of time without any symptoms. In contrast...

  1. Asymptomatic bacteriuria Escherichia coli strains

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Nielsen, E.M.; Klemm, Per

    2006-01-01

    Urinary tract infections (UTIs) affect millions of people each year. Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU) in humans. Persons affected by ABU may carry a particular E. coli strain for extended periods of time without any symptoms. In contrast...

  2. Comparison of clinical categories for Escherichia coli harboring specific qnr and chromosomal-mediated fluoroquinolone resistance determinants according to CLSI and EUCAST.

    Science.gov (United States)

    Machuca, Jesús; Briales, Alejandra; Díaz-de-Alba, Paula; Martínez-Martínez, Luis; Rodríguez-Martínez, José-Manuel; Pascual, Álvaro

    2016-03-01

    EUCAST breakpoints are more restrictive than those defined by CLSI. This study highlights the discrepancies between CLSI and EUCAST in a well characterized isogenic Escherichia coli collection and their correlations with specific quinolone resistance mechanisms. The greatest number of discrepancies was observed in strains containing 2-4 resistance mechanisms (MIC values on the borderline of clinical resistance). Bearing in mind that quinolones are concentration dependent antimicrobial agents, small changes in MIC may have relevant consequences for treatment outcomes. Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  3. Emergence of quinolone resistance among extended-spectrum beta-lactamase-producing Enterobacteriaceae in the Central African Republic: genetic characterization

    Directory of Open Access Journals (Sweden)

    Frank Thierry

    2011-08-01

    Full Text Available Abstract Background Cross-resistance to quinolones and beta-lactams is frequent in Enterobacteriaceae, due to the wide use of these antibiotics clinically and in the food industry. Prescription of one of these categories of antibiotic may consequently select for bacteria resistant to both categories. Genetic mechanisms of resistance may be secondary to a chromosomal mutation located in quinolone resistance determining region of DNA gyrase or topoisomerase IV or to a plasmid acquisition. The insertion sequence ISCR1 is often associated with qnr and may favour its dissemination in Gram-negative bacteria. The aim of this study was to determine the genetic mechanism of quinolone resistance among extended-spectrum beta-lactamase-producing Enterobacteriaceae strains in the Central African Republic. Findings Among seventeen ESBL-producing Enterobacteriaceae isolated from urine, pus or stool between January 2003 and October 2005 in the Central African Republic, nine were resistant to ciprofloxacin (seven from community patients and two from hospitalized patients. The ESBL were previously characterized as CTX-M-15 and SHV-12. Susceptibility to nalidixic acid, norfloxacin and ciprofloxacin, and the minimal inhibitory concentrations of these drugs were determined by disc diffusion and agar dilution methods, respectively. The presence of plasmid-borne ISCR1-qnrA region was determined by PCR and amplicons, if any, were sent for sequencing. Quinolone resistance determining region of DNA gyrase gyrA gene was amplified by PCR and then sequenced for mutation characterization. We found that all CTX-M-producing strains were resistant to the tested quinolones. All the isolates had the same nucleotide mutation at codon 83 of gyrA. Two Escherichia coli strains with the highest MICs were shown to harbour an ISCR1-qnrA1 sequence. This genetic association might favour dissemination of resistance to quinolone and perhaps other antibiotics among Enterobacteriaceae

  4. Prevalence and characterization of cefotaxime and ciprofloxacin co-resistant Escherichia coli isolates in retail chicken carcasses and Ground Pork, China.

    Science.gov (United States)

    Xu, Xiao; Cui, Shenghui; Zhang, Fenglan; Luo, Yanping; Gu, Yihai; Yang, Baowei; Li, Fengqin; Chen, Qian; Zhou, Gang; Wang, Yeru; Pang, Lu; Lin, Lan

    2014-02-01

    Retail meat products could serve as an important medium for the transfer of multidrug resistant isolates from food-producing animals to the community. In this study, the prevalence and characteristics of cefotaxime and ciprofloxacin co-resistant Escherichia coli isolates were investigated in retail chicken and ground pork samples from four provinces of China. The isolates were subjected to phylogenetic group typing and antimicrobial susceptibility testing. All isolates were further characterized by pulsed-field gel electrophoresis to determine the genetic relatedness. These isolates were also screened for beta-lactamase genes, quinolone resistance determinants by PCR, and followed by DNA sequence analysis. Cefotaxime and ciprofloxacin co-resistant E. coli isolates with diverse genetic origins were recovered in 31.9% (106/332) of retail meat samples. E. coli isolates of phylogenetic group A were dominant (59.4%, 63/106), and all isolates showed multidrug resistant profiles. The dominant resistant profiles were AMP-CAZ-CTX-CIP-CHL-GEN-SXT-TET (n=43) and AMP-CAZ-CTX-CIP-CHL-SXT-TET (n=43). Point mutations in quinolone resistance determination regions of topoisomerases were identified in all the isolates, and most of the isolates accumulated three (n=78) or four (n=21) point mutations. Plasmid-mediated quinolone-resistant determinants were identified in 68 isolates, including oqxAB (n=66), qnrS1 (n=7), qnrS2 (n=4), and aac(6')-Ib-cr (n=9). Eight subtypes of bla(CTX-M) were identified in 103 E. coli isolates, and blaCTX-M-55 (n=90) was dominant. This study highlights that retail meat could serve as an important reservoir of cefotaxime and ciprofloxacin co-resistant E. coli isolates. It is necessary to evaluate their contribution in the community and hospital infections.

  5. Differential epigenetic compatibility of qnr antibiotic resistance determinants with the chromosome of Escherichia coli.

    Directory of Open Access Journals (Sweden)

    María B Sánchez

    Full Text Available Environmental bacteria harbor a plethora of genes that, upon their horizontal transfer to new hosts, may confer resistance to antibiotics, although the number of such determinants actually acquired by pathogenic bacteria is very low. The founder effect, fitness costs and ecological connectivity all influence the chances of resistance transfer being successful. We examined the importance of these bottlenecks using the family of quinolone resistance determinants Qnr. The results indicate the epigenetic compatibility of a determinant with the host genome to be of great importance in the acquisition and spread of resistance. A plasmid carrying the widely distributed QnrA determinant was stable in Escherichia coli, whereas the SmQnr determinant was unstable despite both proteins having very similar tertiary structures. This indicates that the fitness costs associated with the acquisition of antibiotic resistance may not derive from a non-specific metabolic burden, but from the acquired gene causing specific changes in bacterial metabolic and regulatory networks. The observed stabilization of the plasmid encoding SmQnr by chromosomal mutations, including a mutant lacking the global regulator H-NS, reinforces this idea. Since quinolones are synthetic antibiotics, and since the origin of QnrA is the environmental bacterium Shewanella algae, the role of QnrA in this organism is unlikely to be that of conferring resistance. Its evolution toward this may have occurred through mutations or because of an environmental change (exaptation. The present results indicate that the chromosomally encoded Qnr determinants of S. algae can confer quinolone resistance upon their transfer to E. coli without the need of any further mutation. These results suggest that exaptation is important in the evolution of antibiotic resistance.

  6. Characterization of Escherichia coli isolates from healthy food handlers in hospital.

    Science.gov (United States)

    Luo, Yanping; Cui, Shenghui; Li, Jingyun; Yang, Jiyong; Lin, Lan; Hu, Changqin; Jin, Shaohong; Ye, Liyan; Zhao, Qiang; Ma, Yue

    2011-09-01

    Recent studies have reported that Escherichia coli in fecal samples of healthy humans could also serve as important reservoirs of drug-resistant bacteria. Limited data are available for E. coli-resistant profiles of healthy food handlers in hospitals who provide food service to inpatients and hospital staffs. E. coli isolates were recovered from hospital healthy food handlers, and one random selected isolate from each food handler was subjected to antimicrobial susceptibility testing, phylogenetic typing, and screening for antimicrobial-resistant mechanisms by polymerase chain reaction amplification. Ciprofloxacin-resistant isolates were further characterized by mutation analysis in the quinolone resistance determining regions (QRDRs) of GyrA and ParC. And extended-spectrum β-lactamase (ESBL) producing isolates were screened for bla(CTX-M) by polymerase chain reaction amplification and DNA sequence analysis. In total, more than 50% (47/92) of E. coli isolates from healthy food handlers showed multidrug-resistant profiles and 50% (46/92) isolates carried intI. Resistance prevalence of the B2 phylogenetic group was significantly lower than that of the non-B2 groups for all tested antimicrobials (p hospital food handlers of multidrug-resistant E. coli makes it important to introduce control measures such as improved biosecurity to ensure that they do not pass through the food service and limit inpatient therapeutic options.

  7. Shiga Toxin Producing Escherichia coli.

    Science.gov (United States)

    Bryan, Allen; Youngster, Ilan; McAdam, Alexander J

    2015-06-01

    Shiga toxin-producing Escherichia coli (STEC) is among the common causes of foodborne gastroenteritis. STEC is defined by the production of specific toxins, but within this pathotype there is a diverse group of organisms. This diversity has important consequences for understanding the pathogenesis of the organism, as well as for selecting the optimum strategy for diagnostic testing in the clinical laboratory. This review includes discussions of the mechanisms of pathogenesis, the range of manifestations of infection, and the several different methods of laboratory detection of Shiga toxin-producing E coli.

  8. Ciprofloxacin-resistant Escherichia coli in Central Greece: mechanisms of resistance and molecular identification

    Directory of Open Access Journals (Sweden)

    Mavroidi Angeliki

    2012-12-01

    Full Text Available Abstract Background Fluoroquinolone resistant E. coli isolates, that are also resistant to other classes of antibiotics, is a significant challenge to antibiotic treatment and infection control policies. In Central Greece a significant increase of ciprofloxacin-resistant Escherichia coli has occurred during 2011, indicating the need for further analysis. Methods A total of 106 ciprofloxacin-resistant out of 505 E. coli isolates consecutively collected during an eight months period in a tertiary Greek hospital of Central Greece were studied. Antimicrobial susceptibility patterns and mechanisms of resistance to quinolones were assessed, whereas selected isolates were further characterized by multilocus sequence typing and β-lactamase content. Results Sequence analysis of the quinolone-resistance determining region of the gyrA and parC genes has revealed that 63% of the ciprofloxacin-resistant E. coli harbored a distinct amino acid substitution pattern (GyrA:S83L + D87N; ParC:S80I + E84V, while 34% and 3% carried the patterns GyrA:S83L + D87N; ParC:S80I and GyrA:S83L + D87N; ParC:S80I + E84G respectively. The aac (6’-1b-cr plasmid-mediated quinolone resistance determinant was also detected; none of the isolates was found to carry the qnrA, qnrB and qnrS. Genotyping of a subset of 35 selected ciprofloxacin-resistant E. coli by multilocus sequence typing has revealed the presence of nine sequence types; ST131 and ST410 were the most prevalent and were exclusively correlated with hospital and health care associated infections, while strains belonging to STs 393, 361 and 162 were associated with community acquired infections. The GyrA:S83L + D87N; ParC:S80I + E84V substitution pattern was found exclusively among ST131 ciprofloxacin-resistant E. coli. Extended-spectrum β-lactamase-positive ST131 ciprofloxacin-resistant isolates produced CTX-M-type enzymes; eight the CTX-M-15 and one the CTX-M-3 variant. CTX-M-1 like and KPC-2 enzymes were detected

  9. Mechanisms of drug resistance: quinolone resistance.

    Science.gov (United States)

    Hooper, David C; Jacoby, George A

    2015-09-01

    Quinolone antimicrobials are synthetic and widely used in clinical medicine. Resistance emerged with clinical use and became common in some bacterial pathogens. Mechanisms of resistance include two categories of mutation and acquisition of resistance-conferring genes. Resistance mutations in one or both of the two drug target enzymes, DNA gyrase and DNA topoisomerase IV, are commonly in a localized domain of the GyrA and ParE subunits of the respective enzymes and reduce drug binding to the enzyme-DNA complex. Other resistance mutations occur in regulatory genes that control the expression of native efflux pumps localized in the bacterial membrane(s). These pumps have broad substrate profiles that include quinolones as well as other antimicrobials, disinfectants, and dyes. Mutations of both types can accumulate with selection pressure and produce highly resistant strains. Resistance genes acquired on plasmids can confer low-level resistance that promotes the selection of mutational high-level resistance. Plasmid-encoded resistance is due to Qnr proteins that protect the target enzymes from quinolone action, one mutant aminoglycoside-modifying enzyme that also modifies certain quinolones, and mobile efflux pumps. Plasmids with these mechanisms often encode additional antimicrobial resistances and can transfer multidrug resistance that includes quinolones. Thus, the bacterial quinolone resistance armamentarium is large.

  10. A molecular analysis of quinolone-resistant Haemophilus influenzae: validation of the mutations in Quinolone Resistance-Determining Regions.

    Science.gov (United States)

    Shoji, Hisashi; Shirakura, Tetsuro; Fukuchi, Kunihiko; Takuma, Takahiro; Hanaki, Hideaki; Tanaka, Kazuo; Niki, Yoshihito

    2014-04-01

    The mechanism of quinolone-resistance is considered to be amino acid mutations in the type II topoisomerase. We validated the genetic mechanisms of quinolone resistance in Haemophilus influenzae. We obtained 29 H. influenzae strains from a nationwide surveillance program in Japan (including 11 quinolone-resistant strains [moxifloxacin: MFLX or levofloxacin MIC ≥2 μg/ml]). We analyzed the sequences of the Quinolone Resistance-Determining Regions (QRDRs) in GyrA, GyrB, ParC and ParE. Furthermore, we induced resistance in susceptible strains by exposing them to quinolone, and investigated the relationship between mutations in the QRDRs and the MICs. Five amino acid substitutions in GyrA (at Ser84 and Asp88) and ParC (at Gly82, Ser84 and Glu88) were found to be closely related to the MICs. The strains with a MFLX MIC of 0.125-1 and 2-4 μg/ml had one and two mutations, respectively. The strains with a MFLX MIC of ≥8 μg/ml had three or more mutations. The strains with induced resistance with MFLX MICs of 0.5-1 and ≥2 μg/ml also had one and two mutations, respectively. We confirmed that these five mutations strongly contribute to quinolone resistance and found that the degree of resistance is related to the number of the mutations. In addition, the three strains of 18 susceptible strains (16.7%) also had a single mutation. These strains may therefore be in the initial stage of quinolone resistance. Currently, the frequency of quinolone-resistant H. influenzae is still low. However, as has occurred with β-lactams, an increase in quinolone use may lead to more quinolone-resistant strains.

  11. Exploring the contribution of efflux on the resistance to fluoroquinolones in clinical isolates of Escherichia coli.

    Science.gov (United States)

    Paltansing, Sunita; Tengeler, Anouk C; Kraakman, Margriet E M; Claas, Eric C J; Bernards, Alexandra T

    2013-12-01

    Resistance to ciprofloxacin in Escherichia coli is increasing parallel to increased use of fluoroquinolones both in The Netherlands and in other European countries. The objective was to investigate the contribution of active efflux and expression of outer membrane proteins (OMPs) in a collection of clinical E. coli isolates collected at a clinical microbiology department in a Dutch hospital. Forty-seven E. coli isolates a wide range of ciprofloxacin minimum inhibitory concentrations and known mutations in the quinolone resistance determining region were included. A fluorometric determination of bisbenzimide efflux was used two different efflux pump inhibitors and compared to quantitative reverse transcription-polymerase chain reaction (qRT-PCR) for the expression levels of acrA, acrB, tolC, yhiV, and mdfA efflux pump genes and the OMPs ompF and ompX. Six isolates (12.7%) showed increased efflux. Although in 35 isolates (76%), overexpression of ≥1 efflux pump genes using qRT-PCR was present. Only the combined overexpression of acrAB-TolC and mdfA correlated with the phenotypic efflux assay using glucose/carbonyl cyanide m-chlorophenylhydrazone with glucose. Thus, efflux was involved in ciprofloxacin resistance in a limited number of E. coli isolates collected at a clinical microbiology department in a Dutch hospital complementing other resistance mechanisms.

  12. Plasmidic qnrA3 enhances Escherichia coli fitness in absence of antibiotic exposure.

    Directory of Open Access Journals (Sweden)

    Adrien Michon

    Full Text Available The widespread presence of plasmid-mediated quinolone resistance determinants, particularly qnr genes, has become a current issue. By protecting DNA-gyrase from quinolones, Qnr proteins confer a low level quinolone resistance that is not sufficient to explain their emergence. Since Qnr proteins were hypothesized to act as DNA-binding protein regulators, qnr genes could have emerged by providing a selective advantage other than antibiotic resistance. We investigated host fitness of Escherichia coli isogenic strains after acquisition of the qnrA3 gene, inserted either alone onto a small plasmid (pBR322, or harbored on a large conjugative native plasmid, pHe96(qnrA3 found in a clinical isolate. The isogenic strains were derived from the susceptible E. coli CFT073, a virulent B2 group strain known to infect bladder and kidneys in a mouse model of pyelonephritis. In vitro experiments included growth analysis by automatic spectrophotometry and flow cytometry, and competitions with CFU enumeration. In vivo experiments included infection with each strain and pairwise competitions in absence of antimicrobial exposure. As controls for our experiments we used mutations known to reduce fitness (rpsL K42N mutation or to enhance fitness (tetA deletion in pBR322. E. coli CFT073 transformed with pBRAM(PBR322-qnrA3 had significantly higher maximal OD than E. coli CFT073 transformed with pBR322 or pBR322ΔtetA, and in vivo competitions were more often won by the qnrA3 carrying strain (24 victories vs. 9 loss among 42 competitions, p = 0.001. In contrast, when pHe96(qnrA3 was introduced by conjugation in E. coli CFT073, it exerted a fitness cost shown by an impaired growth observed in vitro and in vivo and a majority of lost competitions (33/35, p<0.0001. In conclusion, qnrA3 acquisition enhanced bacterial fitness, which may explain qnr emergence and suggests a regulation role of qnr. However, fitness was reduced when qnrA3 was inserted onto multidrug

  13. Rapid and sensitive detection of fluoroquinolone-resistant Escherichia coli from urine samples using a genotyping DNA microarray.

    Science.gov (United States)

    Yu, Xiaolei; Susa, Milorad; Weile, Jan; Knabbe, Cornelius; Schmid, Rolf D; Bachmann, Till T

    2007-10-01

    Urinary tract infections (UTI) are among the most common bacterial infections in humans, with Escherichia coli being the major cause of infection. Fluoroquinolone resistance of uropathogenic E. coli has increased significantly over the last decade. In this study a microarray-based assay was developed and applied, which provides a rapid, sensitive and specific detection of fluoroquinolone-resistant E. coli in urine. The capture probes were designed against previously identified and described hotspots for quinolone resistance (codons 83 and 87 of gyrA). The key goals of this development were to reduce assay time while increasing the sensitivity and specificity as compared with a pilot version of a gyrA genotyping DNA microarray. The performance of the assay was demonstrated with pure cultures of 30 E. coli isolates as well as with urine samples spiked with 6 E. coli isolates. The microarray results were confirmed by standard DNA sequencing and were in full agreement with the phenotypic antimicrobial susceptibility testing using standard methods. The DNA microarray test displayed an assay time of 3.5h, a sensitivity of 100CFU/ml, and the ability to detect fluoroquinolone-resistant E. coli in the presence of a 10-fold excess of fluoroquinolone-susceptible E. coli cells. As a consequence, we believe that this microarray-based determination of antibiotics resistance has a true potential for the application in clinical routine laboratories in the future.

  14. Prevalence and characterisation of quinolone resistance mechanisms in Salmonella spp.

    Science.gov (United States)

    Wasyl, Dariusz; Hoszowski, Andrzej; Zając, Magdalena

    2014-07-16

    The study was focused on characterisation of quinolone resistance mechanisms in Salmonella isolated from animals, food, and feed between 2008 and 2011. Testing of Minimal Inhibitory Concentrations revealed 6.4% of 2680 isolates conferring ciprofloxacin resistance. Simultaneously 37.7% and 40.8% were accounted for, respectively, nalidixic acid and ciprofloxacin Non Wild-Type populations. Amplification and sequencing of quinolone resistance determining region of topoisomerases genes in 44 isolates identified multiple amino-acid substitutions in gyrA at positions Ser83 (N=22; → Leu, → Phe, → Tyr), Asp87 (N=22; → Asn, → Gly, → Tyr) and parC (Thr57Ser, N=23; Ala141Ser, N=1). No relevant mutations were identified in gyrB and parE. Twelve patterns combining one or two substitutions were related to neither serovar nor ciprofloxacin MIC. In 92 isolates suspected for plasmid mediated quinolone resistance two qnr alleles were found: qnrS1 (or qnrS3; N=50) and qnrB19 (or qnrB10; N=24). Additionally, two isolates with chromosomally encoded mechanisms carried qnrS1 and qnrS2. All tested isolates were negative for qnrA, qnrC, qnrD, qepA, aac(6')-Ib-cr. Both chromosomal and plasmid mediated quinolone resistance determinants were found in several Salmonella serovars and Pulsed Field Gel Electrophoresis was used to assess phylogenetic similarity of selected isolates (N=82). Salmonella Newport was found to accumulate quinolone resistance determinants and the serovar was spreading clonally with either variable gyrA mutations, qnrS1/S3, or qnrB10/B19. Alternatively, various determinants are dispersed among related S. Enteritidis isolates. Antimicrobial selection pressure, multiple resistance determinants and scenarios for their acquisition and spread make extremely difficult to combat quinolone resistance.

  15. Apigenin as an anti-quinolone-resistance antibiotic.

    Science.gov (United States)

    Morimoto, Yuh; Baba, Tadashi; Sasaki, Takashi; Hiramatsu, Keiichi

    2015-12-01

    We previously reported the first 'reverse antibiotic' (RA), nybomycin (NYB), which showed a unique antimicrobial activity against Staphylococcus aureus strains. NYB specifically suppressed the growth of quinolone-resistant S. aureus strains but was not effective against quinolone-susceptible strains. Although NYB was first reported in 1955, little was known about its unique antimicrobial activity because it was before the synthesis of the first quinolone ('old quinolone'), nalidixic acid, in 1962. Following our re-discovery of NYB, we looked for other RAs among natural substances that act on quinolone-resistant bacteria. Commercially available flavones were screened against S. aureus, including quinolone-resistant strains, and their minimum inhibitory concentrations (MICs) were compared using the microbroth dilution method. Some of the flavones screened showed stronger antimicrobial activity against quinolone-resistant strains than against quinolone-susceptible ones. Amongst them, apigenin (API) was the most potent in its RA activity. DNA cleavage assay showed that API inhibited DNA gyrase harbouring the quinolone resistance mutation gyrA(Ser84Leu) but did not inhibit 'wild-type' DNA gyrase that is sensitive to levofloxacin. An API-susceptible S. aureus strain Mu50 was also selected using agar plates containing 20mg/L API. Whole-genome sequencing of selected mutant strains was performed and frequent back-mutations (reverse mutations) were found among API-resistant strains derived from the API-susceptible S. aureus strains. Here we report that API represents another molecular class of natural antibiotic having RA activity against quinolone-resistant bacteria.

  16. Robust growth of Escherichia coli.

    Science.gov (United States)

    Wang, Ping; Robert, Lydia; Pelletier, James; Dang, Wei Lien; Taddei, Francois; Wright, Andrew; Jun, Suckjoon

    2010-06-22

    The quantitative study of the cell growth has led to many fundamental insights in our understanding of a wide range of subjects, from the cell cycle to senescence. Of particular importance is the growth rate, whose constancy represents a physiological steady state of an organism. Recent studies, however, suggest that the rate of elongation during exponential growth of bacterial cells decreases cumulatively with replicative age for both asymmetrically and symmetrically dividing organisms, implying that a "steady-state" population consists of individual cells that are never in a steady state of growth. To resolve this seeming paradoxical observation, we studied the long-term growth and division patterns of Escherichia coli cells by employing a microfluidic device designed to follow steady-state growth and division of a large number of cells at a defined reproductive age. Our analysis of approximately 10(5) individual cells reveals a remarkable stability of growth whereby the mother cell inherits the same pole for hundreds of generations. We further show that death of E. coli is not purely stochastic but is the result of accumulating damages. We conclude that E. coli, unlike all other aging model systems studied to date, has a robust mechanism of growth that is decoupled from cell death.

  17. Large IncHI2-plasmids encode extended-spectrum β-lactamases (ESBLs) in Enterobacter spp. bloodstream isolates, and support ESBL-transfer to Escherichia coli.

    Science.gov (United States)

    Nilsen, E; Haldorsen, B C; Sundsfjord, A; Simonsen, G S; Ingebretsen, A; Naseer, U; Samuelsen, O

    2013-11-01

    We investigated the prevalence of extended-spectrum β-lactamases (ESBLs) in Enterobacter spp. bloodstream isolates from 19 hospital laboratories in Norway during 2011. A total of 62/230 (27%) isolates were resistant to third-generation cephalosporins and four (1.7%) were ESBL-positive; blaCTX -M-15 (n = 3) and blaSHV -12 (n = 1). This is comparable to the prevalence of ESBLs in clinical isolates of Escherichia coli and Klebsiella pneumoniae in Norway during the same period. All ESBL-positive isolates were multidrug resistant (MDR) and harboured plasmid-mediated quinolone resistance. Three isolates supported transfer of large IncHI2-plasmids harbouring ESBL- and MDR-encoding genes to E. coli recipients by in vitro conjugation.

  18. High prevalence and variability of CTX-M-15-producing and fluoroquinolone-resistant Escherichia coli observed in stray dogs in rural Angola.

    Science.gov (United States)

    Albrechtova, Katerina; Kubelova, Michaela; Mazancova, Jana; Dolejska, Monika; Literak, Ivan; Cizek, Alois

    2014-08-01

    Antimicrobial resistance (AMR) represents a serious problem globally, but it is especially pronounced in the tropics, where pressure of infectious diseases is high. We examined resistance in Escherichia coli colonizing gastrointestinal tracts of 17 dogs which have never received antimicrobial treatment, living in central rural Angola. Emphasis was placed on extended-spectrum beta-lactamases (ESBL) and plasmid-mediated quinolone resistance (PMQR). Resistance-carrying plasmids were characterized in size, group of incompatibility and ability to conjugate. Isolates were compared by their pulsed-field gel electrophoresis (PFGE) profiles. Detailed description of 19 E. coli isolates with either ESBL or PMQR genes carried on multiresistant plasmids of different groups of incompatibility indicates that dogs, despite never being treated by antibiotics, are important reservoirs and transmitters of AMR in the study area.

  19. Complete Sequence of a KPC-Producing IncN Multidrug-Resistant Plasmid from an Epidemic Escherichia coli Sequence Type 131 Strain in China

    Science.gov (United States)

    Chen, Liang; Hu, Hongyan; Chavda, Kalyan D.; Zhao, Shulong; Liu, Renkun; Liang, Hui; Zhang, Wei; Wang, Xiumei; Jacobs, Michael R.; Bonomo, Robert A.

    2014-01-01

    We report here the nucleotide sequence of a novel blaKPC-2-harboring incompatibility group N (IncN) plasmid, pECN580, from a multidrug-resistant Escherichia coli sequence type 131 (ST131) isolate recovered from Beijing, China. pECN580 harbors β-lactam resistance genes blaKPC-2, blaCTX-M-3, and blaTEM-1; aminoglycoside acetyltransferase gene aac(6′)-Ib-cr; quinolone resistance gene qnrS1; rifampin resistance gene arr-3; and trimethoprim resistance gene dfrA14. The emergence of a blaKPC-2-harboring multidrug-resistant plasmid in an epidemic E. coli ST131 clone poses a significant potential threat in community and hospital settings. PMID:24395232

  20. Quinolone co-resistance in ESBL- or AmpC-producing Escherichia coli from an Indian urban aquatic environment and their public health implications.

    Science.gov (United States)

    Bajaj, Priyanka; Kanaujia, Pawan Kumar; Singh, Nambram Somendro; Sharma, Shalu; Kumar, Shakti; Virdi, Jugsharan Singh

    2016-01-01

    Quinolone and β-lactam antibiotics constitute major mainstay of treatment against infections caused by pathogenic Escherichia coli. Presence of E. coli strains expressing co-resistance to both these antibiotic classes in urban aquatic environments which are consistently being used for various anthropogenic activities represents a serious public health concern. From a heterogeneous collection of 61 E. coli strains isolated from the river Yamuna traversing through the National Capital Territory of Delhi (India), those harboring blaCTX-M-15 (n = 10) or blaCMY-42 (n = 2) were investigated for co-resistance to quinolones and the molecular mechanisms thereof. Resistance was primarily attributed to amino acid substitutions in the quinolone resistance-determining regions (QRDRs) of GyrA (S83L ± D87N) and ParC (S80I ± E84K). One of the E. coli strains, viz., IPE, also carried substitutions in GyrB and ParE at positions Ser492→Asn and Ser458→Ala, respectively. The phenotypically susceptible strains nevertheless carried plasmid-mediated quinolone resistance (PMQR) gene, viz., qnrS, which showed co-transfer to the recipient quinolone-sensitive E. coli J53 along with the genes encoding β-lactamases and led to increase in minimal inhibitory concentrations of quinolone antibiotics. To the best of our knowledge, this represents first report of molecular characterization of quinolone co-resistance in E. coli harboring genes for ESBLs or AmpC β-lactamases from a natural aquatic environment of India. The study warrants true appreciation of the potential of urban aquatic environments in the emergence and spread of multi-drug resistance and underscores the need to characterize resistance genetic elements vis-à-vis their public health implications, irrespective of apparent phenotypic resistance.

  1. Presence of multi-drug resistant pathogenic Escherichia coli in the San Pedro River located in the State of Aguascalientes, Mexico.

    Science.gov (United States)

    Ramírez Castillo, Flor Y; Avelar González, Francisco J; Garneau, Philippe; Márquez Díaz, Francisco; Guerrero Barrera, Alma L; Harel, Josée

    2013-01-01

    Contamination of surface waters in developing countries is a great concern. Treated and untreated wastewaters have been discharged into rivers and streams, leading to possible waterborne infection outbreaks and may represent a significant dissemination mechanism of antibiotic resistance genes. In this study, the water quality of San Pedro River, the main river and pluvial collector of the Aguascalientes State, Mexico was assessed. Thirty sample locations were tested throughout the River. The main physicochemical parameters of water were evaluated. Results showed high levels of fecal pollution as well as inorganic and organic matter abundant enough to support the heterotrophic growth of microorganisms. These results indicate poor water quality in samples from different locations. One hundred and fifty Escherichia coli were collected and screened by PCR for several virulence genes. Isolates were classified as either pathogenic (n = 91) or commensal (n = 59). The disc diffusion method was used to determine antimicrobial susceptibility to 13 antibiotics. Fifty-two percent of the isolates were resistant to at least one antimicrobial agent and 30.6% were multi-resistant. Eighteen E. coli strains were quinolone resistant of which 16 were multi-resistant. Plasmid-mediated quinolone resistance (PMQR) genes were detected in 12 isolates. Mutations at the Ser-83→Leu and/or Asp-87→Asn in the gyrA gene were detected as well as mutations at the Ser-80→Ile in parC. An E. coli microarray (Maxivirulence V 3.1) was used to characterize the virulence and antimicrobial resistance genes profiles of the fluoroquinolone-resistant isolates. Antimicrobial resistance genes such as bla TEM, sulI, sulII, dhfrIX, aph3 (strA), and tet (B) as well as integrons were found in fluoroquinolone (FQ) resistance E. coli strains. The presence of potential pathogenic E. coli and antibiotic resistance in San Pedro River such as FQ resistant E. coli could pose a potential threat to human and animal

  2. Characteristics of cefotaxime-resistant Escherichia coli from wild birds in the Netherlands.

    Science.gov (United States)

    Veldman, Kees; van Tulden, Peter; Kant, Arie; Testerink, Joop; Mevius, Dik

    2013-12-01

    Cloacal swabs from carcasses of Dutch wild birds obtained in 2010 and 2011 were selectively cultured on media with cefotaxime to screen for the presence of extended-spectrum β-lactamase (ESBL)/AmpC-producing Escherichia coli. Subsequently, all cefotaxime-resistant E. coli isolates were tested by broth microdilution and microarray. The presence of ESBL/AmpC and coexisting plasmid-mediated quinolone resistance (PMQR) genes was confirmed by PCR and sequencing. To determine the size of plasmids and the location of ESBL and PMQR genes, S1 pulsed-field gel electrophoresis (PFGE) was performed on transformants, followed by Southern blot hybridization. The study included 414 cloacal swabs originating from 55 different bird species. Cefotaxime-resistant E. coli isolates were identified in 65 birds (15.7%) from 21 different species. In all, 65 cefotaxime-resistant E. coli ESBL/AmpC genes were detected, mainly comprising variants of blaCTX-M and blaCMY-2. Furthermore, PMQR genes [aac(6')-lb-cr, qnrB1, and qnrS1] coincided in seven cefotaxime-resistant E. coli isolates. Overall, replicon typing of the ESBL/AmpC-carrying plasmids demonstrated the predominant presence of IncI1 (n = 31) and variants of IncF (n = 18). Our results indicate a wide dissemination of ESBL and AmpC genes in wild birds from The Netherlands, especially among aquatic-associated species (waterfowl, gulls, and waders). The identified genes and plasmids reflect the genes found predominantly in livestock animals as well as in humans.

  3. Mechanisms of quinolone resistance in Escherichia coli: characterization of nfxB and cfxB, two mutant resistance loci decreasing norfloxacin accumulation.

    OpenAIRE

    Hooper, D C; Wolfson, J S; Souza, K S; Ng, E Y; McHugh, G L; Swartz, M N

    1989-01-01

    Two genetic loci selected for norfloxacin (nfxB) and ciprofloxacin (cfxB) resistance were characterized. Both mutations have previously been shown to confer pleiotropic resistance to quinolones, chloramphenicol, and tetracycline and to decrease expression of porin outer-membrane protein OmpF. nfxB was shown to map at about 19 min and thus to be genetically distinct from ompF (21 min), and cfxB was shown to be very closely linked to marA (34 min). cfxB was dominant over cfxB+ in merodiploids, ...

  4. Escherichia coli transcriptional regulatory network

    Directory of Open Access Journals (Sweden)

    Agustino Martinez-Antonio

    2011-06-01

    Full Text Available Escherichia coli is the most well-know bacterial model about the function of its molecular components. In this review are presented several structural and functional aspects of their transcriptional regulatory network constituted by transcription factors and target genes. The network discussed here represent to 1531 genes and 3421 regulatory interactions. This network shows a power-law distribution with a few global regulators and most of genes poorly connected. 176 of genes in the network correspond to transcription factors, which form a sub-network of seven hierarchical layers where global regulators tend to be set in superior layers while local regulators are located in the lower ones. There is a small set of proteins know as nucleoid-associated proteins, which are in a high cellular concentrations and reshape the nucleoid structure to influence the running of global transcriptional programs, to this mode of regulation is named analog regulation. Specific signal effectors assist the activity of most of transcription factors in E. coli. These effectors switch and tune the activity of transcription factors. To this type of regulation, depending of environmental signals is named the digital-precise-regulation. The integration of regulatory programs have place in the promoter region of transcription units where it is common to observe co-regulation among global and local TFs as well as of TFs sensing exogenous and endogenous conditions. The mechanistic logic to understand the harmonious operation of regulatory programs in the network should consider the globalism of TFs, their signal perceived, coregulation, genome position, and cellular concentration. Finally, duplicated TFs and their horizontal transfer influence the evolvability of members of the network. The most duplicated and transferred TFs are located in the network periphery.

  5. Structure of Escherichia coli tryptophanase.

    Science.gov (United States)

    Ku, Shao Yang; Yip, Patrick; Howell, P Lynne

    2006-07-01

    Pyridoxal 5'-phosphate (PLP) dependent tryptophanase has been isolated from Escherichia coli and its crystal structure has been determined. The structure shares the same fold with and has similar quaternary structure to Proteus vulgaris tryptophanase and tyrosine-phenol lyase, but is found in a closed conformation when compared with these two enzymes. The tryptophanase structure, solved in its apo form, does not have covalent PLP bound in the active site, but two sulfate ions. The sulfate ions occupy the phosphoryl-binding site of PLP and the binding site of the alpha-carboxyl of the natural substrate tryptophan. One of the sulfate ions makes extensive interactions with both the transferase and PLP-binding domains of the protein and appears to be responsible for holding the enzyme in its closed conformation. Based on the sulfate density and the structure of the P. vulgaris enzyme, PLP and the substrate tryptophan were modeled into the active site. The resulting model is consistent with the roles of Arg419 in orienting the substrate to PLP and acidifying the alpha-proton of the substrate for beta-elimination, Lys269 in the formation and decomposition of the PLP quinonoid intermediate, Arg230 in orienting the substrate-PLP intermediates in the optimal conformation for catalysis, and His463 and Tyr74 in determining substrate specificity and suggests that the closed conformation observed in the structure could be induced by substrate binding and that significant conformational changes occur during catalysis. A catalytic mechanism for tryptophanase is proposed. Since E. coli tryptophanase has resisted forming diffraction-quality crystals for many years, the molecular surface of tryptophanase has been analyzed in various crystal forms and it was rationalized that strong crystal contacts occur on the flat surface of the protein and that the size of crystal contact surface seems to correlate with the diffraction quality of the crystal.

  6. Structure of Escherichia Coli Tryptophanase

    Energy Technology Data Exchange (ETDEWEB)

    Ku,S.; Yip, P.; Howell, P.

    2006-01-01

    Pyridoxal 5'-phosphate (PLP) dependent tryptophanase has been isolated from Escherichia coli and its crystal structure has been determined. The structure shares the same fold with and has similar quaternary structure to Proteus vulgaris tryptophanase and tyrosine-phenol lyase, but is found in a closed conformation when compared with these two enzymes. The tryptophanase structure, solved in its apo form, does not have covalent PLP bound in the active site, but two sulfate ions. The sulfate ions occupy the phosphoryl-binding site of PLP and the binding site of the {alpha}-carboxyl of the natural substrate tryptophan. One of the sulfate ions makes extensive interactions with both the transferase and PLP-binding domains of the protein and appears to be responsible for holding the enzyme in its closed conformation. Based on the sulfate density and the structure of the P. vulgaris enzyme, PLP and the substrate tryptophan were modeled into the active site. The resulting model is consistent with the roles of Arg419 in orienting the substrate to PLP and acidifying the {alpha}-proton of the substrate for {beta}-elimination, Lys269 in the formation and decomposition of the PLP quinonoid intermediate, Arg230 in orienting the substrate-PLP intermediates in the optimal conformation for catalysis, and His463 and Tyr74 in determining substrate specificity and suggests that the closed conformation observed in the structure could be induced by substrate binding and that significant conformational changes occur during catalysis. A catalytic mechanism for tryptophanase is proposed. Since E. coli tryptophanase has resisted forming diffraction-quality crystals for many years, the molecular surface of tryptophanase has been analyzed in various crystal forms and it was rationalized that strong crystal contacts occur on the flat surface of the protein and that the size of crystal contact surface seems to correlate with the diffraction quality of the crystal.

  7. Genes under positive selection in Escherichia coli

    DEFF Research Database (Denmark)

    Petersen, Lise; Bollback, J.P.; Dimmic, Matt

    2007-01-01

    We used a comparative genomics approach to identify genes that are under positive selection in six strains of Escherichia coli and Shigella flexneri, including five strains that are human pathogens. We find that positive selection targets a wide range of different functions in the E. coli genome...

  8. Fosfomycin Resistance in Escherichia coli, Pennsylvania, USA.

    Science.gov (United States)

    Alrowais, Hind; McElheny, Christi L; Spychala, Caressa N; Sastry, Sangeeta; Guo, Qinglan; Butt, Adeel A; Doi, Yohei

    2015-11-01

    Fosfomycin resistance in Escherichia coli is rare in the United States. An extended-spectrum β-lactamase-producing E. coli clinical strain identified in Pennsylvania, USA, showed high-level fosfomycin resistance caused by the fosA3 gene. The IncFII plasmid carrying this gene had a structure similar to those found in China, where fosfomycin resistance is commonly described.

  9. Fimbrial adhesins from extraintestinal Escherichia coli

    DEFF Research Database (Denmark)

    Klemm, Per; Hancock, Viktoria; Schembri, Mark A.

    2010-01-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) represent an important subclass of E. coli that cause a wide spectrum of diseases in human and animal hosts. Fimbriae are key virulence factors of ExPEC strains. These long surface located rod-shaped organelles mediate receptor-specific attachment...

  10. Infectious endocarditis caused by Escherichia coli

    DEFF Research Database (Denmark)

    Lauridsen, Trine Kiilerich; Arpi, Magnus; Fritz-Hansen, Thomas

    2011-01-01

    Although Escherichia coli is among the most common causes of Gram-negative bacteraemia, infectious endocarditis (IE) due to this pathogen is rare. A 67-y-old male without a previous medical history presented with a new mitral regurgitation murmur and persisting E. coli bacteraemia in spite of broad...

  11. Genes under positive selection in Escherichia coli

    DEFF Research Database (Denmark)

    Petersen, Lise; Bollback, J.P.; Dimmic, Matt

    2007-01-01

    We used a comparative genomics approach to identify genes that are under positive selection in six strains of Escherichia coli and Shigella flexneri, including five strains that are human pathogens. We find that positive selection targets a wide range of different functions in the E. coli genome...

  12. Prevalence of Escherichia coli O157

    NARCIS (Netherlands)

    Abdissa, Rosa; Haile, Woynshet; Fite, Akafete Teklu; Beyi, Ashenafi Feyisa; Agga, Getahun E.; Edao, Bedaso Mammo; Tadesse, Fanos; Korsa, Mesula Geloye; Beyene, Takele; Beyene, Tariku Jibat; Zutter, De Lieven; Cox, Eric; Goddeeris, Bruno Maria

    2017-01-01

    Background: There is paucity of information regarding the epidemiology of Escherichia coli O157: H7 in developing countries. In this study, we investigated the occurrence of E. coli O157: H7 associated with beef cattle at processing plants and at retail shops in Ethiopia. Methods: Various samples

  13. Escherichia coli survival in waters: Temperature dependence

    Science.gov (United States)

    Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q10 mo...

  14. Strategies for Protein Overproduction in Escherichia coli.

    Science.gov (United States)

    Mott, John E.

    1984-01-01

    Examines heterologous expression in Escherichia coli and the role of regulatory sequences which control gene expression at transcription resulting in abundant production of messenger RNA and regulatory sequences in mRNA which promote efficient translation. Also examines the role of E. coli cells in stabilizing mRNA and protein that is…

  15. ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli

    OpenAIRE

    ANGGREINI, RAHAYU

    2015-01-01

    2015 RAHAYU ANGGREINI coli Penelitian ini bertujuan untuk melakukan identifikasi cemaran bakteri E. coli O157:H7 pada daging sapi di kota Makassar. Sampel pada penelitian ini sebanyak 72 sampel Kata Kunci : Daging sapi, pasar tradisional, E. coli, E. coli O157:H7, kontaminasi bakteri, identifikasi E. coli O157:H7.

  16. ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli

    OpenAIRE

    ANGGREINI, RAHAYU

    2015-01-01

    2015 RAHAYU ANGGREINI coli Penelitian ini bertujuan untuk melakukan identifikasi cemaran bakteri E. coli O157:H7 pada daging sapi di kota Makassar. Sampel pada penelitian ini sebanyak 72 sampel Kata Kunci : Daging sapi, pasar tradisional, E. coli, E. coli O157:H7, kontaminasi bakteri, identifikasi E. coli O157:H7.

  17. Multidrug Resistance in Quinolone-Resistant Gram-Negative Bacteria Isolated from Hospital Effluent and the Municipal Wastewater Treatment Plant.

    Science.gov (United States)

    Vaz-Moreira, Ivone; Varela, Ana Rita; Pereira, Thamiris V; Fochat, Romário C; Manaia, Célia M

    2016-03-01

    This study is aimed to assess if hospital effluents represent an important supplier of multidrug-resistant (MDR) Gram-negative bacteria that, being discharged in the municipal collector, may be disseminated in the environment and bypassed in water quality control systems. From a set of 101 non-Escherichia coli Gram-negative bacteria with reduced susceptibility to quinolones, was selected a group of isolates comprised by those with the highest indices of MDR (defined as nonsusceptibility to at least one agent in six or more antimicrobial categories, MDR ≥6) or resistance to meropenem or ceftazidime (n = 25). The isolates were identified and characterized for antibiotic resistance phenotype, plasmid-mediated quinolone resistance (PMQR) genes, and other genetic elements and conjugative capacity. The isolates with highest MDR indices were mainly from hospital effluent and comprised ubiquitous bacterial groups of the class Gammaproteobacteria, of the genera Aeromonas, Acinetobacter, Citrobacter, Enterobacter, Klebsiella, and Pseudomonas, and of the class Flavobacteriia, of the genera Chryseobacterium and Myroides. In this group of 25 strains, 19 identified as Gammaproteobacteria harbored at least one PMQR gene (aac(6')-Ib-cr, qnrB, qnrS, or oqxAB) or a class 1 integron gene cassette encoding aminoglycoside, sulfonamide, or carbapenem resistance. Most of the E. coli J53 transconjugants with acquired antibiotic resistance resulted from conjugation with Enterobacteriaceae. These transconjugants demonstrated acquired resistance to a maximum of five classes of antibiotics, one or more PMQR genes and/or a class 1 integron gene cassette. This study shows that ubiquitous bacteria, other than those monitored in water quality controls, are important vectors of antibiotic resistance and can be disseminated from hospital effluent to aquatic environments. This information is relevant to support management options aiming at the control of this public health problem.

  18. Antimicrobial resistance in commensal Escherichia coli isolated from animals at slaughter

    Science.gov (United States)

    Wasyl, Dariusz; Hoszowski, Andrzej; Zając, Magdalena; Szulowski, Krzysztof

    2013-01-01

    Monitoring of antimicrobial resistance in commensal Escherichia coli (N = 3430) isolated from slaughtered broilers, laying hens, turkeys, swine, and cattle in Poland has been run between 2009 and 2012. Based on minimal inhibitory concentration (MIC) microbiological resistance to each of 14 tested antimicrobials was found reaching the highest values for tetracycline (43.3%), ampicillin (42.3%), and ciprofloxacin (39.0%) whereas the lowest for colistin (0.9%), cephalosporins (3.6 ÷ 3.8%), and florfenicol (3.8%). The highest prevalence of resistance was noted in broiler and turkey isolates, whereas it was rare in cattle. That finding along with resistance patterns specific to isolation source might reflect antimicrobial consumption, usage preferences or management practices in specific animals. Regression analysis has identified changes in prevalence of microbiological resistance and shifts of MIC values. Critically important fluoroquinolone resistance was worrisome in poultry isolates, but did not change over the study period. The difference (4.7%) between resistance to ciprofloxacin and nalidixic acid indicated the scale of plasmid-mediated quinolone resistance. Cephalosporin resistance were found in less than 3.8% of the isolates but an increasing trends were observed in poultry and MIC shift in the ones from cattle. Gentamycin resistance was also increasing in E. coli of turkey and cattle origin although prevalence of streptomycin resistance in laying hens decreased considerably. Simultaneously, decreasing MIC for phenicols observed in cattle and layers isolates as well as tetracycline values in E. coli from laying hens prove that antimicrobial resistance is multivariable phenomenon not only directly related to antimicrobial usage. Further studies should elucidate the scope of commensal E. coli as reservoirs of resistance genes, their spread and possible threats for human and animal health. PMID:23935596

  19. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Escherichia coli serological reagents. 866.3255... coli serological reagents. (a) Identification. Escherichia coli serological reagents are devices that consist of antigens and antisera used in serological tests to identify Escherichia coli from...

  20. Increasing quinolone resistance in Salmonella enterica serotype enteritidis

    DEFF Research Database (Denmark)

    Mølbak, K.; Gerner-Smidt, P.; Wegener, Henrik Caspar

    2002-01-01

    Until recently, Salmonella enterica serotype Enteritidis has remained sensitive to most antibiotics. However, national surveillance data from Denmark show that quinolone resistance in S. Enteritidis has increased from 0.8% in 1995 to 8.5% in 2000. These data support concerns that the current use...... of quinolone in food animals leads to increasing resistance in S. Enteritidis and that action should be taken to limit such use....

  1. Virulence repertoire, characterization, and antibiotic resistance pattern analysis of Escherichia coli isolated from backyard layers and their environment in India.

    Science.gov (United States)

    Samanta, Indranil; Joardar, Siddhartha N; Das, Pradip K; Das, Palas; Sar, Tapas K; Dutta, Tapan K; Bandyopadhyay, Samiran; Batabyal, Subhasis; Isore, Devi P

    2014-03-01

    This study was undertaken to observe the prevalence, serogroup, avian pathogenic Escherichia coli (APEC)-associated virulence gene, randomly amplified polymorphic DNA (RAPD) pattern, and antibiotic resistance genes of E. coli in backyard layers and their environment in India. From the 360 samples of healthy layers and their environment, 272 (75.5%) E. coli were isolated. The majority (28.67%) of them were untypeable. Among the studied virulence genes (papC, tsh, iucC, astA), 52 (14.32%) isolates were found to possess astA, including the isolates from the drinking water of the birds (4/272, 1.47%). These strains belonged to 18 different serogroups. Most of the isolates were typeable by RAPD and they produced different patterns. Phenotypic resistance of the isolates was most frequently observed to erythromycin (95.83%), chloramphenicol (87.52%), and cotrimoxazole (78.26%). None of the isolates was found to possess extended-spectrum beta-lactamases (bla(TEM), bla(SHV), bla(CTX-M) or quinolone resistance (qnrA) genes by PCR. The present study was the first attempt in India to assess APEC distribution in backyard poultry production.

  2. Native valve Escherichia coli endocarditis following urosepsis.

    Science.gov (United States)

    Rangarajan, D; Ramakrishnan, S; Patro, K C; Devaraj, S; Krishnamurthy, V; Kothari, Y; Satyaki, N

    2013-05-01

    Gram-negative organisms are a rare cause of infective endocarditis. Escherichia coli, the most common cause of urinary tract infection and gram-negative septicemia involves endocardium rarely. In this case report, we describe infection of native mitral valve by E. coli following septicemia of urinary tract origin in a diabetic male; subsequently, he required prosthetic tissue valve replacement indicated by persistent sepsis and congestive cardiac failure.

  3. 77 FR 9888 - Shiga Toxin-Producing Escherichia coli

    Science.gov (United States)

    2012-02-21

    ... Food Safety and Inspection Service Shiga Toxin-Producing Escherichia coli in Certain Raw Beef Products... manufacturing trimmings for six non-O157 Shiga toxin-producing Escherichia coli (STEC) serogroups (O26, O45..., non-intact product, that are contaminated with Shiga toxin-producing Escherichia coli (STEC) O26,...

  4. The first report of the qnrB19, qnrS1 and aac(6´-Ib-cr genes in urinary isolates of ciprofloxacin-resistant Escherichia coli in Brazil

    Directory of Open Access Journals (Sweden)

    Magna Cristina Paiva

    2012-08-01

    Full Text Available In this study, we investigated the presence of plasmid-mediated quinolone resistance (PMQR genes among 101 ciprofloxacin-resistant urinary Escherichia coli isolates and searched for mutations in the quinolone-resistance-determining regions (QRDRs of the DNA gyrase and topoisomerase IV genes in PMQR-carrying isolates. Eight isolates harboured the qnr and aac(6'-Ib-cr genes (3 qnrS1, 1 qnrB19 and 4 aac(6'-Ib-cr. A mutational analysis of the QRDRs in qnr and aac(6'-Ib-cr-positive isolates revealed mutations in gyrA, parC and parE that might be associated with high levels of resistance to quinolones. No mutation was detected in gyrB. Rare gyrA, parC and parE mutations were detected outside of the QRDRs. This is the first report of qnrB19, qnrS1 and aac(6'-Ib-cr -carrying E. coli isolates in Brazil.

  5. Control of Ribosome Synthesis in Escherichia coli

    DEFF Research Database (Denmark)

    Molin, Søren; Meyenburg, K. von; Måløe, O.

    1977-01-01

    The rate of ribosome synthesis and accumulation in Escherichia coli during the transition after an energy source shift-down was analyzed. The shift was imposed on cultures of stringent and relaxed strains growing in glucose minimal medium by the addition of the glucose analogue {alpha}-methylgluc...

  6. Synergistic effects in mixed Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Reisner, A.; Holler, B.M.; Molin, Søren

    2006-01-01

    the pathways governing development of more complex heterogeneous communities. In this study, we established a laboratory model where biofilm-stimulating effects due to interactions between genetically diverse strains of Escherichia coli were monitored. Synergistic induction of biofilm formation resulting from...

  7. Escherichia Coli--Key to Modern Genetics.

    Science.gov (United States)

    Bregegere, Francois

    1982-01-01

    Mid-nineteenth century work by Mendel on plant hybrids and by Pasteur on fermentation gave birth by way of bacterial genetics to modern-day molecular biology. The bacterium Escherichia Coli has occupied a key position in genetic studies leading from early gene identification with DNA to current genetic engineering using recombinant DNA technology.…

  8. Progressive segregation of the Escherichia coli chromosome

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck; Youngren, Brenda; Hansen, Flemming G.

    2006-01-01

    We have followed the fate of 14 different loci around the Escherichia coli chromosome in living cells at slow growth rate using a highly efficient labelling system and automated measurements. Loci are segregated as they are replicated, but with a marked delay. Most markers segregate in a smooth...

  9. Leaner and meaner genomes in Escherichia coli

    DEFF Research Database (Denmark)

    Ussery, David

    2006-01-01

    A 'better' Escherichia coli K-12 genome has recently been engineered in which about 15% of the genome has been removed by planned deletions. Comparison with related bacterial genomes that have undergone a natural reduction in size suggests that there is plenty of scope for yet more deletions....

  10. Compaction of isolated Escherichia coli nucleoids

    NARCIS (Netherlands)

    Wegner, Anna S.; Wintraecken, Kathelijne; Spurio, Roberto; Woldringh, Conrad L.; Vries, de Renko; Odijk, Theo

    2016-01-01

    Escherichia coli nucleoids were compacted by the inert polymer polyethylene glycol (PEG) in the presence of the H-NS protein. The protein by itself appears to have little impact on the size of the nucleoids as determined by fluorescent microscopy. However, it has a significant impact on the nucle

  11. Experimental and Clinical Studies on Fluoroquinolone-insusceptible Escherichia coli Isolated from Patients with Urinary Tract Infections from 1994 to 2007

    Directory of Open Access Journals (Sweden)

    Watanabe,Toyohiko

    2009-10-01

    Full Text Available Urinary tract infections (UTIs due to fluoroquinolone-insusceptible Escherichia coli have become increasingly common in recent years. We investigated the potential relationships between clinical measures to combat fluoroquinolone-insusceptible E. coli and experimental analyses on E. coli isolates. Over a 14-year period from 1994 through 2007, a total of 828 E. coli isolates were collected from patients (one isolate per patient with UTI at the urology ward of Okayama University Hospital. We analyzed the mutations in quinolone resistance-determining regions of DNA gyrase (gyrA and topoisomerase IV (parC. The production of biofilm by these isolates was also examined and the associated medical records were retrospectively reviewed. Seven of 189 (3.7% strains from uncomplicated UTIs and 82 of 639 (12.8% strains from complicated UTIs were insusceptible to fluoroquinolones. Amino acid replacements of type II topoisomerases were frequently observed at positions 83 and 87 in GyrA and at positions 80 and 84 in ParC. No significant difference in the biofilm-forming capabilities was observed between fluoroquinolone-susceptible and -insusceptible E. coli. Our study suggests that biofilm formation of fluoroquinolone-insusceptible E. coli isolates is not a major mechanism of resistance in patients with UTI.

  12. Escherichia coli in Europe: An Overview

    Directory of Open Access Journals (Sweden)

    Nerino Allocati

    2013-11-01

    Full Text Available Escherichia coli remains one of the most frequent causes of several common bacterial infections in humans and animals. E. coli is the prominent cause of enteritis, urinary tract infection, septicaemia and other clinical infections, such as neonatal meningitis. E. coli is also prominently associated with diarrhoea in pet and farm animals. The therapeutic treatment of E. coli infections is threatened by the emergence of antimicrobial resistance. The prevalence of multidrug-resistant E. coli strains is increasing worldwide principally due to the spread of mobile genetic elements, such as plasmids. The rise of multidrug-resistant strains of E. coli also occurs in Europe. Therefore, the spread of resistance in E. coli is an increasing public health concern in European countries. This paper summarizes the current status of E. coli strains clinically relevant in European countries. Furthermore, therapeutic interventions and strategies to prevent and control infections are presented and discussed. The article also provides an overview of the current knowledge concerning promising alternative therapies against E. coli diseases.

  13. Antibiotic resistance in Escherichia coli in husbandry animals: the African perspective.

    Science.gov (United States)

    Alonso, C A; Zarazaga, M; Ben Sallem, R; Jouini, A; Ben Slama, K; Torres, C

    2017-05-01

    In the last few years, different surveillances have been published in Africa, especially in northern countries, regarding antimicrobial resistance among husbandry animals. Information is still scarce, but the available data show a worrying picture. Although the highest resistance rates have been described against tetracycline, penicillins and sulphonamides, prevalence of plasmid-mediated quinolone resistance genes and extended spectrum β-lactamase (ESBL) are being increasingly reported. Among ESBLs, the CTX-M-1 group was dominant in most African surveys. Within this group, CTX-M-15 was the main variant both in animals and humans, except in Tunisia where CTX-M-1 was more frequently detected among Escherichia coli from poultry. Certain blaCTX-M-15 -harbouring clones (ST131/B2 or ST405/D) are mainly identified in humans, but they have also been reported in livestock species from Tanzania, Nigeria or Tunisia. Moreover, several reports suggest an inter-host circulation of specific plasmids (e.g. blaCTX-M-1 -carrying IncI1/ST3 in Tunisia, IncY- and Inc-untypeable replicons co-harbouring qnrS1 and blaCTX-M-15 in Tanzania and the worldwide distributed blaCTX-M-15 -carrying IncF-type plasmids). International trade of poultry meat seems to have contributed to the spread of other ESBL variants, such as CTX-M-14, and clones. Furthermore, first descriptions of OXA-48- and OXA-181-producing E. coli have been recently documented in cattle from Egypt, and the emergent plasmid-mediated colistin resistance mcr-1 gene has been also identified in chickens from Algeria, Tunisia and South Africa. These data reflect the urgent need of a larger regulation in the use of veterinary drugs and the implementation of surveillance programmes in order to decelerate the advance of antimicrobial resistance in this continent. © 2017 The Society for Applied Microbiology.

  14. Pathogenomics of uropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    J Agarwal

    2012-01-01

    Full Text Available Subset of faecal E. coli that can enter, colonize urinary tract and cause infection are known as uropathogenic E. coli (UPEC. UPEC strains act as opportunistic intracellular pathogens taking advantage of host susceptibility using a diverse array of virulence factors. Presence of specific virulence associated genes on genomic/pathogenicity islands and involvement of horizontal gene transfer appears to account for evolution and diversity of UPEC. Recent success in large-scale genome sequencing and comparative genomics has helped in unravelling UPEC pathogenomics. Here we review recent findings regarding virulence characteristics of UPEC and mechanisms involved in pathogenesis of urinary tract infection.

  15. Infektionen mit darmpathogenen Escherichia coli.

    NARCIS (Netherlands)

    Friedrich, Alexander; Stein, Jürgen; Dignass, Axel

    2001-01-01

    E. coli ist ein wesentlicher Bestandteil der physiologischen Darmflora des Menschen. Die üblicherweise im Darm vorkommenden Kolibakterien sind apathogen und für den Menschen eher nützlich (Sonnenborn u. Greinwald 1990). Allerdings kennen wir bei dieser Bakterienspezies auch ein breites Spektrum von

  16. Survival of Escherichia coli in stormwater biofilters.

    Science.gov (United States)

    Chandrasena, G I; Deletic, A; McCarthy, D T

    2014-04-01

    Biofilters are widely adopted in Australia for stormwater treatment, but the reported removal of common faecal indicators (such as Escherichia coli (E. coli)) varies from net removal to net leaching. Currently, the underlying mechanisms that govern the faecal microbial removal in the biofilters are poorly understood. Therefore, it is important to study retention and subsequent survival of faecal microorganisms in the biofilters under different biofilter designs and operational characteristics. The current study investigates how E. coli survival is influenced by temperature, moisture content, sunlight exposure and presence of other microorganisms in filter media and top surface sediment. Soil samples were taken from two different biofilters to investigate E. coli survival under controlled laboratory conditions. Results revealed that the presence of other microorganisms and temperature are vital stressors which govern the survival of E. coli captured either in the top surface sediment or filter media, while sunlight exposure and moisture content are important for the survival of E. coli captured in the top surface sediment compared to that of the filter media. Moreover, increased survival was found in the filter media compared to the top sediment, and sand filter media was found be more hostile than loamy sand filter media towards E. coli survival. Results also suggest that the contribution from the tested environmental stressors on E. coli survival in biofilters will be greatly affected by the seasonality and may vary from one site to another.

  17. Hydrogen production by recombinant Escherichia coli strains

    Science.gov (United States)

    Maeda, Toshinari; Sanchez‐Torres, Viviana; Wood, Thomas K.

    2012-01-01

    Summary The production of hydrogen via microbial biotechnology is an active field of research. Given its ease of manipulation, the best‐studied bacterium Escherichia coli has become a workhorse for enhanced hydrogen production through metabolic engineering, heterologous gene expression, adaptive evolution, and protein engineering. Herein, the utility of E. coli strains to produce hydrogen, via native hydrogenases or heterologous ones, is reviewed. In addition, potential strategies for increasing hydrogen production are outlined and whole‐cell systems and cell‐free systems are compared. PMID:21895995

  18. The evolution of the Escherichia coli phylogeny.

    Science.gov (United States)

    Chaudhuri, Roy R; Henderson, Ian R

    2012-03-01

    Escherichia coli is familiar to biologists as a classical model system, ubiquitous in molecular biology laboratories around the world. Outside of the laboratory, E. coli strains exist as an almost universal component of the lower-gut flora of humans and animals. Although usually a commensal, E. coli has an alter ego as a pathogen, and is associated with diarrhoeal disease and extra-intestinal infections. The study of E. coli diversity predates the availability of molecular data, with strains initially distinguished by serotyping and metabolic profiling, and genomic diversity illustrated by DNA hybridisation. The quantitative study of E. coli diversity began with the application of multi-locus enzyme electrophoresis (MLEE), and has progressed with the accumulation of nucleotide sequence data, from single genes through multi-locus sequence typing (MLST) to whole genome sequencing. Phylogenetic methods have shed light on the processes of genomic evolution in this extraordinarily diverse species, and revealed the origins of pathogenic E. coli strains, including members of the phylogenetically indistinguishable "genus"Shigella. In May and June 2011, an outbreak of haemorrhagic uraemic syndrome in Germany was linked to a strain of enterohaemorrhagic E. coli (EHEC) O104:H4. Application of high-throughput sequencing technologies allowed the genome and origins of the outbreak strain to be characterised in real time as the outbreak was in progress.

  19. Identification and Prevalence of Escherichia coli and Escherichia coli O157: H7 in Foods

    Directory of Open Access Journals (Sweden)

    Ancuta Mihaela Rotar

    2013-11-01

    Full Text Available The objective of this study is to investigate the incidence of Escherichia coli in animal and non-animal foods, and mainly the incidence of the serotype O157: H7 producing verotoxin. The presence of common Escherichia coli and Escherichia coli O157: H7 in various foods (of animal and non animal origin was performed in Transylvania area. We analyzed a total of one hundred forty-one samples of minced meat, one hundred twenty-six samples of meat , twenty six samples of meat products, five samples of alcoholic beverages, three samples of seafood, one hundred samples of cheese from pasteurized milk, seventeen samples of butter, four samples of vegetables and one sample of milk powder, using the standard cultural method and Vidas Eco method for E. coli O157: H7 strains. E. coli was identified in 50 samples of minced meat, 55 samples of meat prepared, 4 samples of meat products, 2 samples of alcoholic beverages, 25 samples of cheese from pasteurized milk, 6 samples of butter and 1 sample of vegetables. In this study were not been identified any foods contaminated with the E. coli O157: H7 serotype. The results of this reasearch have demostrated that E. coli wich represents a hygienic indicator of recent food contamination, can be destroyed with heat treatment and hygienic handling of foods. Our country over the years has been among the few countries where the incidence of the E. coli O157: H7 serotype has been minimal.

  20. Automatic tracking of Escherichia coli bacteria.

    Science.gov (United States)

    Xie, Jun; Khan, Shahid; Shah, Mubarak

    2008-01-01

    In this paper, we present an automatic method for estimating the trajectories of Escherichia coli bacteria from in vivo phase-contrast microscopy videos. To address the low-contrast boundaries in cellular images, an adaptive kernel-based technique is applied to detect cells in sequence of frames. Then a novel matching gain measure is introduced to cope with the challenges such as dramatic changes of cells' appearance and serious overlapping and occlusion. For multiple cell tracking, an optimal matching strategy is proposed to improve the handling of cell collision and broken trajectories. The results of successful tracking of Escherichia coli from various phase-contrast sequences are reported and compared with manually-determined trajectories, as well as those obtained from existing tracking methods. The stability of the algorithm with different parameter values is also analyzed and discussed.

  1. Escherichia coli necrotizing fasciitis in Hirschsprung's disease

    Directory of Open Access Journals (Sweden)

    Manal A. Alsaif

    2015-04-01

    Full Text Available Necrotizing fasciitis is a rare post-operative complication of Hirschsprung's disease. Very recently the only previous case of necrotizing fasciitis following a Soave procedure was reported with the etiologic agent being Pseudomonas aeruginosa. Here we are reporting the second case of necrotizing fasciitis following a Soave procedure caused by an extended spectrum beta lactamase harboring strain of Escherichia coli which is a rare pathogen in type II necrotizing fasciitis.

  2. Homology requirements for recombination in Escherichia coli.

    OpenAIRE

    Watt, V M; Ingles, C J; Urdea, M S; Rutter, W J

    1985-01-01

    The DNA sequence homology required for recombination in Escherichia coli has been determined by measuring the recombination frequency between insulin DNA in a miniplasmid pi VX and a homologous sequence in a bacteriophage lambda vector. A minimum of approximately equal to 20 base pairs in a completely homologous segment is required for significant recombination. There is an exponential increase in the frequency of recombination when the length of homologous DNA is increased from 20 base pairs...

  3. Multiplex PCR Assay for Identification of Human Diarrheagenic Escherichia coli

    OpenAIRE

    Toma, Claudia; Lu, Yan; Higa, Naomi; Nakasone, Noboru; Isabel CHINEN; Baschkier, Ariela; Rivas, Marta; Iwanaga, Masaaki

    2003-01-01

    A multiplex PCR assay for the identification of human diarrheagenic Escherichia coli was developed. The targets selected for each category were eae for enteropathogenic E. coli, stx for Shiga toxin-producing E. coli, elt and est for enterotoxigenic E. coli, ipaH for enteroinvasive E. coli, and aggR for enteroaggregative E. coli. This assay allowed the categorization of a diarrheagenic E. coli strain in a single reaction tube.

  4. Multiplex PCR Assay for Identification of Human Diarrheagenic Escherichia coli

    OpenAIRE

    2003-01-01

    A multiplex PCR assay for the identification of human diarrheagenic Escherichia coli was developed. The targets selected for each category were eae for enteropathogenic E. coli, stx for Shiga toxin-producing E. coli, elt and est for enterotoxigenic E. coli, ipaH for enteroinvasive E. coli, and aggR for enteroaggregative E. coli. This assay allowed the categorization of a diarrheagenic E. coli strain in a single reaction tube.

  5. Siderophore production by uropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Vagrali Manjula

    2009-01-01

    Full Text Available Urinary tract infection (UTI is one of the most frequently encountered problems in ambulatory medicine. The present study was designed to determine siderophore production as the urovirulence factor of Escherichia coli isolated from the patients of UTI. A total of 160 strains of E. coli isolated from urine of patients with clinically diagnosed UTI were included in the study and 50 fecal isolates of E. coli, siderophore production was seen in 156 (97.5%. In 50 fecal isolates, siderophore production was seen in 2 (4%. Siderophore production has been shown to be more frequent in E. coli from patients with UTI, than in fecal isolates. The results suggest that siderophore production positive strains can be considered as UPEC. Thus, although a great deal has been learned regarding E. coli virulence mechanisms in UTI, much remains to be learned and the practical application of our growing understanding of E. coli virulence factors to the prevention and treatment of UTI has to be continued.

  6. Differentiation between Shigella, enteroinvasive Escherichia coli (EIEC) and noninvasive Escherichia coli.

    Science.gov (United States)

    van den Beld, M J C; Reubsaet, F A G

    2012-06-01

    Shigella causes bacillary dysentery and is classified into four species based on their antigen characteristics. This classification does not reflect genetic relatedness; in fact, Shigella species are so related to Escherichia coli , they should be classified as one distinctive species in the genus Escherichia. The differentiation of Shigella and E. coli is even more complicated with the description of enteroinvasive E. coli (EIEC). EIEC are strains that possess some of the biochemical characteristics of E. coli and have the ability to cause dysentery using the same method of invasion as Shigella does. Sequencing of multiple housekeeping genes indicates that EIEC is more related to Shigella than to non-invasive E. coli. Shigella and EIEC evolved from the same ancestor and form a single pathovar within E. coli. Shigella and EIEC could be separated from other E. coli by a PCR targeting the ipaH-gene; this is a multicopy gene exclusively found in all Shigella and EIEC. It is possible to differentiate Shigella and all E. coli, including EIEC, by using multiple tests, including ipaH-gene PCR, physiological and biochemical typing and serological typing. Based on literature study, a key is designed for daily use in diagnostic laboratories to identify Shigella and all E. coli.

  7. Cellular chain formation in Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk; Klemm, Per

    2009-01-01

    In this study we report on a novel structural phenotype in Escherichia coli biofilms: cellular chain formation. Biofilm chaining in E. coli K-12 was found to occur primarily by clonal expansion, but was not due to filamentous growth. Rather, chain formation was the result of intercellular......; type I fimbriae expression significantly reduced cellular chain formation, presumably by steric hindrance. Cellular chain formation did not appear to be specific to E coli K-12. Although many urinary tract infection (UTI) isolates were found to form rather homogeneous, flat biofilms, three isolates......, including the prototypic asymptomatic bacteriuria strain, 83972, formed highly elaborate cellular chains during biofilm growth in human urine. Combined, these results illustrate the diversity of biofilm architectures that can be observed even within a single microbial species....

  8. Interaction between Escherichia coli and lunar fines

    Science.gov (United States)

    Johansson, K. R.

    1983-01-01

    A sample of mature lunar fines (10084.151) was solubilized to a high degree (about 17 percent) by the chelating agent salicylic acid (0.01. M). The neutralized (pH adjusted to 7.0) leachate was found to inhibit the growth of Escherichia coli (ATCC 259922) in a minimial mineral salts glucose medium; however, the inhibition was somewhat less than that caused by neutralized salicylic acid alone. The presence of lunar fines in the minimal medium was highly stimulatory to growth of E. coli following an early inhibitory response. The bacterium survived less well in the lunar leachate than in distilled water, no doubt because of the salicylate. It was concluded that the sample of lunar soil tested has nutritional value to E. coli and that certain products of fermentation helped to solubilize the lunar soil.

  9. Presence of qnr gene in Escherichia coli and Klebsiella pneumoniae resistant to ciprofloxacin isolated from pediatric patients in China

    Directory of Open Access Journals (Sweden)

    Wang Chuanqing

    2008-05-01

    Full Text Available Abstract Background Quinolone resistance in Enterobacteriaceae results mainly from mutations in type II DNA topoisomerase genes and/or changes in the expression of outer membrane and efflux pumps. Several recent studies have indicated that plasmid-mediated resistance mechanisms also play a significant role in fluoroquinolone resistance, and its prevalence is increasing worldwide. In China, the presence of the qnr gene in the clinical isolates of Enterobacteriaceae has been reported, but this transmissible quinolone resistance gene has not been detected in strains isolated singly from pediatric patients. Because quinolones associated with a variety of adverse side effects on children, they are not authorized for pediatric use. This study therefore aimed to investigate the presence of the qnr gene in clinical isolates of E. coli and K. pneumoniae from pediatric patients in China. Methods A total 213 of non-repetitive clinical isolates resistant to ciprofloxacin from E. coli and K. pneumoniae were collected from hospitalized patients at five children's hospital in Beijing, Shanghai, Guangzhou, and Chongqing. The isolates were screened for the plasmid-mediated quinolone resistance genes of qnrA, qnrB, and qnrS by PCR. Transferability was examined by conjugation with the sodium azide-resistant E. coli J53. All qnr-positive were analyzed for clonality by enterobacterial repetitive intergenic consensus (ERIC-PCR. Results The study found that 19 ciprofloxacin-resistant clinical isolates of E. coli and K. pneumoniae were positive for the qnr gene, and most of the qnr positive strains were ESBL producers. Conjugation experiments showed that quinolone resitance could be transferred to recipients. Apart from this, different DNA banding patterns were obtained by ERIC-PCR from positive strains, which means that most of them were not clonally related. Conclusion This report on transferable fluoroquinolone resistance due to the qnr gene among E. coli and K

  10. Clonal relationship between human and avian ciprofloxacin-resistant Escherichia coli isolates in North-Eastern Algeria.

    Science.gov (United States)

    Agabou, A; Lezzar, N; Ouchenane, Z; Khemissi, S; Satta, D; Sotto, A; Lavigne, J-P; Pantel, A

    2016-02-01

    The objectives of this study were to determine rates, patterns, and mechanisms of antibiotic resistance, and to assess connections between chicken commensal, human commensal, and pathogenic ciprofloxacin-resistant Escherichia coli isolates. All E. coli isolates collected from chickens, their farmers, and patients in the Constantine region (North-east Algeria) were analyzed for bla and plasmid-mediated quinolone resistance (PMQR) gene contents, phylogroups, Rep-PCR profiles, and multilocus sequence types. A high prevalence of resistance to fluoroquinolones (51.4 % to ciprofloxacin) was recorded in avian isolates. Of these, 22.2 % carried the aac(6')-Ib-cr gene, whereas lower resistance levels to these antibiotics were recorded in chicken farmers' isolates. None of the commensal isolates harbored the qnr, qepA, or oqxAB genes. One human pathogenic isolate was ertapenem-resistant and harbored the bla OXA-48 gene, 84 showed an extended-spectrum β-lactamase phenotype, with bla CTX-M-15 gene prevalent in 87.2 % of them. Seventy isolates were resistant to fluoroquinolones, with aac(6')-Ib-cr present in 72.8 %, qnrB in 5.7 %, and qnrS in 10 %. Three Rep-PCR profiles were common to chicken commensal and human pathogenic isolates (phylogroups D and B1; ST21, ST48, and ST471 respectively); one was found in both chicken and chicken-farmer commensal strains (D; ST108), while another profile was identified in a chicken-farmer commensal strain and a human pathogenic one (B1; ST19). These findings suggest clonal and epidemiologic links between chicken and human ciprofloxacin-resistant E. coli isolates and the important role that poultry may play in the epidemiology of human E. coli infections in the Constantine region.

  11. Presence of multi-drug resistant pathogenic Escherichia coli in the San Pedro River located in the State of Aguascalientes, Mexico.

    Directory of Open Access Journals (Sweden)

    Flor Yazmin Ramirez Castillo

    2013-06-01

    Full Text Available Contamination of surface waters in developing countries is a great concern. Treated and untreated wastewaters have been discharged into rivers and streams, leading to possible waterborne infection outbreaks and may represent a significant dissemination mechanism of antibiotic resistance genes. In this study, the water quality of San Pedro River, the main river and pluvial collector of the Aguascalientes State, Mexico was assessed. Thirty sample locations were tested throughout the River. The main physicochemical parameters of water were evaluated. Results showed high levels of fecal pollution as well as inorganic and organic matter abundant enough to support the heterotrophic growth of microorganisms. These results indicate poor water quality in samples from different locations. One hundred and fifty Escherichia coli were collected and screened by PCR for several virulence genes. Isolates were classified as either pathogenic (n = 91 or commensal (n = 59. The disc diffusion method was used to determine antimicrobial susceptibility to 13 antibiotics. Fifty-two percent of the isolates were resistant to at least one antimicrobial agent and 30.6% were multi-resistant. Eighteen E. coli strains were quinolone resistant of which 16 were multi-resistant. Plasmid-mediated quinolone resistance genes were detected in 12 isolates. Mutations at the Ser-83→Leu and/or Asp-87→Asn in the gyrA gene were detected as well as mutations at the Ser-80→Ile in parC. An E. coli microarray (Maxivirulence V 3.1 was used to characterize the virulence and antimicrobial resistance genes profiles of the fluoroquinolone-resistant isolates. Antimicrobial resistance genes such as blaTEM, sulI, sulII, dhfrIX, aph3 (strA and tet (B as well as integrons were found in fluoroquinolone resistance E. coli strains. The presence of potential pathogenic E. coli and antibiotic resistance in San Pedro River such as fluoroquinolone resistant E. coli could pose a potential threat to human

  12. Intramammary challenge with Escherichia coli following immunization with a curli-producing Escherichia coli.

    Science.gov (United States)

    Todhunter, D A; Smith, K L; Hogan, J S; Nelson, L

    1991-03-01

    Holstein and Jersey cattle were immunized with a curli-producing strain of Escherichia coli (pCRL65/A012) or a noncurli-producing strain (pUC18/HB101) to determine differences in resistance to establishment of experimental intramammary infection. Cows (n = 6 per group) were immunized at 14 d prior to drying off, 7 d of involution, and at calving with 3 x 10(10) E. coli in Freund's Incomplete Adjuvant. At 30 d of lactation, one mammary quarter of each cow was infused with a wild strain of E. coli (727). Escherichia coli 727 was isolated from a naturally occurring intramammary infection and produced curli. All challenged quarters became infected, and all cows developed acute clinical mastitis. Geometric mean duration of intramammary infections was 6 d for both immunization groups. All infections were spontaneously eliminated within 10 d. No differences occurred between immunization groups in blood selenium and glutathione peroxidase activity, plasma selenium, number of E. coli 727 isolated from secretion after challenge, rectal temperature and SCC response, clinical status of mammary quarters, or DMI. Reduction in milk production after challenge was greater for cows immunized with E. coli pCRL65/A012. Immunization of dairy cattle with a curli-producing strain of E. coli did not protect against experimental intramammary challenge during lactation.

  13. Ethanol production by Escherichia coli KO11; Producao de etanol por Escherichia coli KO11

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Katia Gianni de Carvalho [Sao Paulo Univ., SP (Brazil). Faculdade de Ciencias Farmaceuticas. Lab. de Microbiologia de Alimentos]. E-mail: gianni@usp.br; Takahashi, Caroline Maki; Alterthum, Flavio [Sao Paulo Univ., SP (Brazil). Inst. de Ciencias Biomedicas. Dept. de Microbiologia

    2002-08-01

    This paper discusses the potential use of Escherichia coli KO11 in production of ethanol, based on observation that this organism can efficiently metabolize sugar complex moistures obtained from the acid hydrolysis of lignocellulose materials such as sugar-cane bagasse, corncob, corn husk, Pinus sp and oak wood.

  14. Enteropathogenic Escherichia coli: foe or innocent bystander?

    Science.gov (United States)

    Hu, J; Torres, A G

    2015-08-01

    Enteropathogenic Escherichia coli (EPEC) remain one the most important pathogens infecting children and they are one of the main causes of persistent diarrhoea worldwide. Historically, typical EPEC (tEPEC), defined as those isolates with the attaching and effacement (A/E) genotype (eae(+)), which possess bfpA(+) and lack the stx(-) genes are found strongly associated with diarrhoeal cases. However, occurrence of atypical EPEC (aEPEC; eae(+)bfpA(-)stx(-)) in diarrhoeal and asymptomatic hosts has made investigators question the role of these pathogens in human disease. Current epidemiological data are helping to answer the question of whether EPEC is mainly a foe or an innocent bystander during infection.

  15. Escherichia coli fliAZY operon.

    OpenAIRE

    Mytelka, D S; Chamberlin, M J

    1996-01-01

    We have cloned the Escherichia coli fliAZY operon, which contains the fliA gene (the alternative sigma factor sigma F) and two novel genes, fliZ and fliY. Transcriptional mapping of this operon shows two start sites, one of which is preceded by a canonical E sigma F-dependent consensus and is dependent on sigma F for expression in vivo and in vitro. We have overexpressed and purified sigma F and demonstrated that it can direct core polymerase to E sigma F-dependent promoters. FliZ and FliY ar...

  16. Global gene expression in Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Schembri, Mark; Kjærgaard, K.; Klemm, Per

    2003-01-01

    in expression have no current defined function. These genes, as well as those induced by stresses relevant to biofilm growth such as oxygen and nutrient limitation, may be important factors that trigger enhanced resistance mechanisms of sessile communities to antibiotics and hydrodynamic shear forces.......It is now apparent that microorganisms undergo significant changes during the transition from planktonic to biofilm growth. These changes result in phenotypic adaptations that allow the formation of highly organized and structured sessile communities, which possess enhanced resistance...... to antimicrobial treatments and host immune defence responses. Escherichia coli has been used as a model organism to study the mechanisms of growth within adhered communities. In this study, we use DNA microarray technology to examine the global gene expression profile of E. coli during sessile growth compared...

  17. Genes under positive selection in Escherichia coli

    DEFF Research Database (Denmark)

    Petersen, Lise; Bollback, Jonathan P; Dimmic, Matt

    2007-01-01

    We used a comparative genomics approach to identify genes that are under positive selection in six strains of Escherichia coli and Shigella flexneri, including five strains that are human pathogens. We find that positive selection targets a wide range of different functions in the E. coli genome......, including cell surface proteins such as beta barrel porins, presumably because of the involvement of these genes in evolutionary arms races with other bacteria, phages, and/or the host immune system. Structural mapping of positively selected sites on trans-membrane beta barrel porins reveals...... that the residues under positive selection occur almost exclusively in the extracellular region of the proteins that are enriched with sites known to be targets of phages, colicins, or the host immune system. More surprisingly, we also find a number of other categories of genes that show very strong evidence...

  18. Production of recombinant avidin in Escherichia coli.

    Science.gov (United States)

    Airenne, K J; Sarkkinen, P; Punnonen, E L; Kulomaa, M S

    1994-06-24

    A recombinant avidin (re-Avd), containing amino acids (aa) 1-123 of the native chicken egg-white Avd, was produced in Escherichia coli. When cells were grown at 37 degrees C production was over 1 microgram/ml, due to altering the codon preference of the first ten codons. The re-Avd was recovered as a soluble protein from cells grown at 25 or 30 degrees C, whereas at 37 degrees C it was mostly insoluble in inclusion bodies. Our results indicated that, despite the potentially harmful biotin-binding activity of Avd, it is possible to produce biologically active Avd in E. coli which then can easily be purified by affinity chromatography on a biotin column in a single step.

  19. Escherichia coli growth under modeled reduced gravity

    Science.gov (United States)

    Baker, Paul W.; Meyer, Michelle L.; Leff, Laura G.

    2004-01-01

    Bacteria exhibit varying responses to modeled reduced gravity that can be simulated by clino-rotation. When Escherichia coli was subjected to different rotation speeds during clino-rotation, significant differences between modeled reduced gravity and normal gravity controls were observed only at higher speeds (30-50 rpm). There was no apparent affect of removing samples on the results obtained. When E. coli was grown in minimal medium (at 40 rpm), cell size was not affected by modeled reduced gravity and there were few differences in cell numbers. However, in higher nutrient conditions (i.e., dilute nutrient broth), total cell numbers were higher and cells were smaller under reduced gravity compared to normal gravity controls. Overall, the responses to modeled reduced gravity varied with nutrient conditions; larger surface to volume ratios may help compensate for the zone of nutrient depletion around the cells under modeled reduced gravity.

  20. 尿道感染大肠埃希菌对喹诺酮耐药性及相关因素分析%Drug Resistance and Risk Factors Analysis of Escherichia Coli Isolated from Urinary Tract Infection to Quinolone

    Institute of Scientific and Technical Information of China (English)

    张昭勇; 张吉才; 杜毅

    2013-01-01

    Objective To investigate the drug resistance and risk factors of Escherichia coli isolated from urinary tract infection (UTI) to quinolone. Methods Drug resistance of 705 strains of Escherichia coli isolated from 749 urine specimens of UTI from 2010 to 2011 in our hospital were detected and divided into the resistance group and the sensitive group according to sensitiveness to quinolone, and the risk factors of the quinolone resistance strains were analyzed. Results In 705 strains isolates E. coli, there were 474 strains (67. 2% ) of quinolone resistance in the resistance group, 231 strains (32. 8% ) of quinolone sensitiveness in the sensitive group and there was no carbapenem resistant strain. The differences in resistance rates of amoxicillin/clavulanic acid, cefotaxime, ceftazidime, aztreonam, piperacillin, amikacin, bactrim, gentamicin and cefepime of the two groups were statistically significant (P<0. 05) . Logistic regression analysis showed that the proportion of female patients, drug use of tert-cephalosporins and quinolones, urinary drainage and bacterium producing extended spectrum β lactamases (ESBLS) were independent risk factors of quinolone resistance E. coli. The differences in hospital stay and cost of the two groups were statistically significant (P<0. 05). Conclusion The detection rate of quinolone resistance escherichia coli isolated from UIT is high. The emergence of resistant strains is related to antibiotic application, invasive handling and bacterial variation. To strengthen the independent risk factors regulation can effectively prevent and control spread of infection.%目的 探讨尿道感染(urinary tract infection,UIT)大肠埃希菌对喹诺酮耐药性及其相关因素.方法 对我院2010-2011年749例UIT尿液标本中分离的705株大肠埃希菌的耐药性进行检测,以对喹诺酮敏感与否分为耐药株组和敏感株组,分析耐药株感染的相关因素.结果 705株大肠埃希菌中对喹诺酮耐药474株(67.2

  1. Escherichia coli O157:H7.

    Science.gov (United States)

    Mead, P S; Griffin, P M

    1998-10-10

    Escherichia coli O157 was first identified as a human pathogen in 1982. One of several Shiga toxin-producing serotypes known to cause human illness, the organism probably evolved through horizontal acquisition of genes for Shiga toxins and other virulence factors. E. coli O157 is found regularly in the faeces of healthy cattle, and is transmitted to humans through contaminated food, water, and direct contact with infected people or animals. Human infection is associated with a wide range of clinical illness, including asymptomatic shedding, non-bloody diarrhoea, haemorrhagic colitis, haemolytic uraemic syndrome, and death. Since laboratory practices vary, physicians need to know whether laboratories in their area routinely test for E. coli O157 in stool specimens. Treatment with antimicrobial agents remains controversial: some studies suggest that treatment may precipitate haemolytic uraemic syndrome, and other studies suggest no effect or even a protective effect. Physicians can help to prevent E. coli O157 infections by counselling patients about the hazards of consuming undercooked ground meat or unpasteurised milk products and juices, and about the importance of handwashing to prevent the spread of diarrhoeal illness, and by informing public-health authorities when they see unusual numbers of cases of bloody diarrhoea or haemolytic uraemic syndrome.

  2. Engineering Escherichia coli for methanol conversion.

    Science.gov (United States)

    Müller, Jonas E N; Meyer, Fabian; Litsanov, Boris; Kiefer, Patrick; Potthoff, Eva; Heux, Stéphanie; Quax, Wim J; Wendisch, Volker F; Brautaset, Trygve; Portais, Jean-Charles; Vorholt, Julia A

    2015-03-01

    Methylotrophic bacteria utilize methanol and other reduced one-carbon compounds as their sole source of carbon and energy. For this purpose, these bacteria evolved a number of specialized enzymes and pathways. Here, we used a synthetic biology approach to select and introduce a set of "methylotrophy genes" into Escherichia coli based on in silico considerations and flux balance analysis to enable methanol dissimilation and assimilation. We determined that the most promising approach allowing the utilization of methanol was the implementation of NAD-dependent methanol dehydrogenase and the establishment of the ribulose monophosphate cycle by expressing the genes for hexulose-6-phosphate synthase (Hps) and 6-phospho-3-hexuloisomerase (Phi). To test for the best-performing enzymes in the heterologous host, a number of enzyme candidates from different donor organisms were selected and systematically analyzed for their in vitro and in vivo activities in E. coli. Among these, Mdh2, Hps and Phi originating from Bacillus methanolicus were found to be the most effective. Labeling experiments using (13)C methanol with E. coli producing these enzymes showed up to 40% incorporation of methanol into central metabolites. The presence of the endogenous glutathione-dependent formaldehyde oxidation pathway of E. coli did not adversely affect the methanol conversion rate. Taken together, the results of this study represent a major advancement towards establishing synthetic methylotrophs by gene transfer.

  3. Escherichia coli as a bioreporter in ecotoxicology.

    Science.gov (United States)

    Robbens, Johan; Dardenne, Freddy; Devriese, Lisa; De Coen, Wim; Blust, Ronny

    2010-11-01

    Ecotoxicological assessment relies to a large extent on the information gathered with surrogate species and the extrapolation of test results across species and different levels of biological organisation. Bacteria have long been used as a bioreporter for genotoxic testing and general toxicity. Today, it is clear that bacteria have the potential for screening of other toxicological endpoints. Escherichia coli has been studied for years; in-depth knowledge of its biochemistry and genetics makes it the most proficient prokaryote for the development of new toxicological assays. Several assays have been designed with E. coli as a bioreporter, and the recent trend to develop novel, better advanced reporters makes bioreporter development one of the most dynamic in ecotoxicology. Based on in-depth knowledge of E. coli, new assays are being developed or existing ones redesigned, thanks to the availability of new reporter genes and new or improved substrates. The technological evolution towards easier and more sensitive detection of different gene products is another important aspect. Often, this requires the redesign of the bacterium to make it compatible with the novel measuring tests. Recent advances in surface chemistry and nanoelectronics open the perspective for advanced reporter based on novel measuring platforms and with an online potential. In this article, we will discuss the use of E. coli-based bioreporters in ecotoxicological applications as well as some innovative sensors awaited for the future.

  4. Antimicrobial susceptibility testing of Escherichia coli strains isolated from urinary tract infections to fluoroquinolones and detection of gyrA mutations in resistant strains

    Directory of Open Access Journals (Sweden)

    Akbari-Nakhjavani F.

    2007-05-01

    Full Text Available Widespread uses of fluoroquinolones have resulted in increasing incidences of resistance against these agents all over the world. The aim of this study was to assess, susceptibility of Escherichia coli strains from patients with Urinary Tract Infection against common fluoroquinolones and detection of mutations in the gyrA gene. Antimicrobial susceptibility testing of 164 E.coli isolates from patients with UTI, was evaluated by disk agar diffusion (DAD and MIC methods. Polymerase chain reaction of E.coli strains were performed by amplification of Quinolone Resistance Determining Region (QRDR of gyrA gene. PCR products were tested by Conformational Sensitive Gel Electrophoresis (CSGE and those with hetrodublexes were selected and examined by DNA sequencing. According to disc agar diffusion, 49.3% were resistant to nalidixic acid, 41.4% to norfloxacin, 44.5% to ofloxacin and 40.2 % to ciprofloxacin. By Minimal Inhibitory Concentration (MIC testing a high-level of resistance (42.1% to ciprofloxacin was observed. Mutations in codons 83 and 87 in all 81 isolates were positive by CSGE method.

  5. Multiple Antimicrobial Resistance and Novel Point Mutation in Fluoroquinolone-Resistant Escherichia coli Isolates from Mangalore, India.

    Science.gov (United States)

    Kogaluru Shivakumaraswamy, Santhosh; Vijaya Kumar, Deekshit; Moleyuru Nagarajappa, Venugopal; Karunasagar, Iddya; Karunasagar, Indrani

    2017-04-26

    Fluoroquinolone resistance in bacteria is usually associated with mutations in the topoisomerase regions. We report a novel point mutation in fluoroquinolone-resistant Escherichia coli strains. E. coli isolated from the environment in and around Mangalore, India, were examined for their antimicrobial resistance profile to 12 antibiotics and for the antibiotic resistance genes by polymerase chain reaction. Of the 67 E. coli isolated, 24 (35.8%) were sensitive to all antibiotics and 43 (64.2%) showed resistance to at least one of the 12 antibiotics used in the study. One isolate (EC10) was resistant to nine of the 12 antibiotics used. Resistance to nalidixic acid was the most common (34.32%), followed by nitrofurantoin (26.86%), tetracycline (22.38%), ampicillin (20.89%), cotrimoxazole (13.43%), ciprofloxacin (11.94%), gentamicin (10.44%), piperacillin/tazobactam (7.46%), chloramphenicol (7.46%), and cefotaxime (4.47%). Least resistance was observed for meropenem (1.49%) and none of the isolates showed resistance to imipenem. All the isolates harbored resistance genes corresponding to their antimicrobial resistance. Few quinolone-resistant isolates carried single point mutation (ser83Leu) and some had double point mutation (Ser83Leu and Asp87Asn) in gyrA. A third novel point mutation was also observed at position 50 with the change in the amino acid from tyrosine to cysteine (Tyr50Cys) in gyrA region. The study throws light on a novel point mutation in fluoroquinolone-resistant isolates. While the study helps to understand the risk and occurrence of antibiotic resistance among gram-negative bacteria from the environment, the alarming rate of antibiotic-resistant bacteria is a cause of concern in addressing infections.

  6. Chromatin architecture and gene expression in Escherichia coli

    DEFF Research Database (Denmark)

    Willenbrock, Hanni; Ussery, David

    2004-01-01

    Two recent genome-scale analyses underscore the importance of DNA topology and chromatin structure in regulating transcription in Escherichia coli.......Two recent genome-scale analyses underscore the importance of DNA topology and chromatin structure in regulating transcription in Escherichia coli....

  7. Escherichia coli O157 infections and unpasteurised milk

    NARCIS (Netherlands)

    Allerberger, F; Wagner, M; Schweiger, P; Rammer, H P; Resch, A; Dierich, M P; Friedrich, A W; Karch, H

    2001-01-01

    We report on two children with Escherichia coli O157 infection, one of whom developed haemolytic uraemic syndrome (HUS). Both had drunk raw cows or goats milk in the week before their illness. Molecular subtyping identified a sorbitol fermenting Escherichia coli O157:H isolate from a dairy cow. This

  8. Escherichia coli O157 infections and unpasteurised milk

    NARCIS (Netherlands)

    Allerberger, F; Wagner, M; Schweiger, P; Rammer, H P; Resch, A; Dierich, M P; Friedrich, A W; Karch, H

    2001-01-01

    We report on two children with Escherichia coli O157 infection, one of whom developed haemolytic uraemic syndrome (HUS). Both had drunk raw cows or goats milk in the week before their illness. Molecular subtyping identified a sorbitol fermenting Escherichia coli O157:H isolate from a dairy cow. This

  9. Production of glycoprotein vaccines in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Ihssen Julian

    2010-08-01

    Full Text Available Abstract Background Conjugate vaccines in which polysaccharide antigens are covalently linked to carrier proteins belong to the most effective and safest vaccines against bacterial pathogens. State-of-the art production of conjugate vaccines using chemical methods is a laborious, multi-step process. In vivo enzymatic coupling using the general glycosylation pathway of Campylobacter jejuni in recombinant Escherichia coli has been suggested as a simpler method for producing conjugate vaccines. In this study we describe the in vivo biosynthesis of two novel conjugate vaccine candidates against Shigella dysenteriae type 1, an important bacterial pathogen causing severe gastro-intestinal disease states mainly in developing countries. Results Two different periplasmic carrier proteins, AcrA from C. jejuni and a toxoid form of Pseudomonas aeruginosa exotoxin were glycosylated with Shigella O antigens in E. coli. Starting from shake flask cultivation in standard complex medium a lab-scale fed-batch process was developed for glycoconjugate production. It was found that efficiency of glycosylation but not carrier protein expression was highly susceptible to the physiological state at induction. After induction glycoconjugates generally appeared later than unglycosylated carrier protein, suggesting that glycosylation was the rate-limiting step for synthesis of conjugate vaccines in E. coli. Glycoconjugate synthesis, in particular expression of oligosaccharyltransferase PglB, strongly inhibited growth of E. coli cells after induction, making it necessary to separate biomass growth and recombinant protein expression phases. With a simple pulse and linear feed strategy and the use of semi-defined glycerol medium, volumetric glycoconjugate yield was increased 30 to 50-fold. Conclusions The presented data demonstrate that glycosylated proteins can be produced in recombinant E. coli at a larger scale. The described methodologies constitute an important step

  10. Prevalence of diarrheagenic Escherichia coli in suckling rabbits

    OpenAIRE

    2016-01-01

    Diarrheagenic Escherichia coli (E. coli) in suckling rabbit causes collibacillosis, which is characterized by sever yellow diarrhea, poor growth and high mortalities. This study was undertaken to investigate the prevalence of diarrheagenic E. coli in suckling rabbits in Egypt. Additionally, expression of some virulence-associated genes in the isolated E. coli serotypes were examined using the polymerase chain reaction. Finally, antibiogram of the identified E. coli serotypes was also investig...

  11. Methane production from kitchen waste using Escherichia coli.

    Science.gov (United States)

    Jayalakshmi, S; Joseph, Kurian; Sukumaran, V

    2007-04-01

    Escherichia coli (E. coli) strain isolated from biogas plant sludge was examined for its ability to enhance biogas from kitchen waste during solid phase anaerobic digestion. The laboratory experiments were conducted for total solid concentrations of 20% and 22%. Kitchen waste was characterized for physico-chemical parameters and laboratory experiments were conducted with and without E. coli strain. It was found that the reactor with E. coli produced 17% more biogas than the reactors that are operated without E. coli strain.

  12. Long term effects of Escherichia coli mastitis.

    Science.gov (United States)

    Blum, Shlomo E; Heller, Elimelech D; Leitner, Gabriel

    2014-07-01

    Escherichia coli is one of the most frequently diagnosed causes of bovine mastitis, and is typically associated with acute, clinical mastitis. The objective of the present study was to evaluate the long term effects of intramammary infections by E. coli on milk yield and quality, especially milk coagulation. Twenty-four Israeli Holstein cows diagnosed with clinical mastitis due to intramammary infection by E. coli were used in this study. Mean lactation number, days in milk (DIM) and daily milk yield (DMY) at the time of infection was 3.3 ± 1.3, 131.7 days ± 78.6 and 45.7 L ± 8.4, respectively. DMY, milk constituents, somatic cells count (SCC), differential leukocytes count and coagulation parameters were subsequently assessed. Two patterns of inflammation were identified: 'short inflammation', characterized by 15% decrease in DMY and >30 days to reach a new maximum DMY (n = 19). The estimated mean loss of marketable milk during the study was 200 L/cow for 'short inflammation' cases, and 1,500 L/cow for 'long inflammation' ones. Significant differences between 'short' and 'long inflammation' effects were found in almost all parameters studied. Long-term detrimental effects on milk quality were found regardless of clinical or bacteriological cure of affected glands.

  13. Cyclomodulins in urosepsis strains of Escherichia coli.

    Science.gov (United States)

    Dubois, Damien; Delmas, Julien; Cady, Anne; Robin, Frédéric; Sivignon, Adeline; Oswald, Eric; Bonnet, Richard

    2010-06-01

    Determinants of urosepsis in Escherichia coli remain incompletely defined. Cyclomodulins (CMs) are a growing functional family of toxins that hijack the eukaryotic cell cycle. Four cyclomodulin types are actually known in E. coli: cytotoxic necrotizing factors (CNFs), cycle-inhibiting factor (Cif), cytolethal distending toxins (CDTs), and the pks-encoded toxin. In the present study, the distribution of CM-encoding genes and the functionality of these toxins were investigated in 197 E. coli strains isolated from patients with community-acquired urosepsis (n = 146) and from uninfected subjects (n = 51). This distribution was analyzed in relation to the phylogenetic background, clinical origin, and antibiotic resistance of the strains. It emerged from this study that strains harboring the pks island and the cnf1 gene (i) were strongly associated with the B2 phylogroup (P, urosepsis origin (P, urosepsis groups, suggesting that the pks island is more important for the colonization process and the cnf1 gene for virulence. pks- or cnf1-harboring strains were significantly associated with susceptibility to antibiotics (amoxicillin, cotrimoxazole, and quinolones [P, <0.001 to 0.043]). Otherwise, only 6% and 1% of all strains harbored the cdtB and cif genes, respectively, with no particular distribution by phylogenetic background, antimicrobial susceptibility, or clinical origin.

  14. Prevalence of ESBLs and PMQR genes in fecal Escherichia coli isolated from the non-human primates in six zoos in China.

    Science.gov (United States)

    Wang, Yang; He, Tao; Han, Jing; Wang, Juan; Foley, Steven L; Yang, Guangyou; Wan, Shuangxiu; Shen, Jianzhong; Wu, Congming

    2012-09-14

    The aim of this study is to characterize the prevalence of extended-spectrum β-lactamases (ESBLs) and plasmid-mediated quinolone resistance (PMQR) genes in Escherichia coli from captive non-human primates. A total of 206 E. coli isolates were collected from primates in six zoos in China in 2009 and their susceptibility to 10 antimicrobials were tested by broth microdilution. The susceptibility patterns of E. coli strains varied greatly among different zoos reflecting different backgrounds of antimicrobial usage. Both the ESBL-encoding genes and the PMQR genes were detected by PCR. Of the 206 strains, 65 (32%) were confirmed as phenotypic ESBL producers with bla(CTX-M) (27%, bla(CTX-M-15), n=31, bla(CTX-M-3), n=23 and bla(CTX-M-14), n=2) mainly mediating the ESBL phenotype. qnrS1 (18%, n=36) and oqxAB (15%, n=31) were the predominant PMQR genes and the prevalence of PMQR genes was much higher among phenotypic ESBL producers than that among phenotypic non-ESBL producers from any zoo. Notably, the PMQR genes qnrS1 and oqxAB and β-lactamase genes bla(TEM-1) and bla(CTX-M-3) were found together in 23 E. coli isolates in two zoos in Shanghai. PFGE analysis of these 23 isolates demonstrated nearly identical PFGE profiles (similarity matrix >97%) indicating this specific E. coli genotype was prevalent in these two zoos. To the best of our knowledge, this is the first report of these four genes coexisting in an E. coli genotype and the first report of antimicrobial resistance profiles in E. coli isolated from primates in China. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Wild Birds, Frequent Carriers of Extended-Spectrum β-Lactamase (ESBL) Producing Escherichia coli of CTX-M and SHV-12 Types.

    Science.gov (United States)

    Alcalá, Leticia; Alonso, Carla Andrea; Simón, Carmen; González-Esteban, Chabier; Orós, Jesús; Rezusta, Antonio; Ortega, Carmelo; Torres, Carmen

    2016-11-01

    To get a better insight into the role of birds as reservoirs of extended-spectrum β-lactamase (ESBL) and plasmidic AmpC β-lactamase (pAmpC) Escherichia coli producers, 100 fecal samples belonging to 15 different wild avian species from Northern Spain were analyzed. Cefotaxime-resistant (CTX(R)) E. coli isolates were identified in 16 of the 100 tested birds, which corresponded to 9 animal species (Gyps fulvus-griffon vulture, Larus michahellis-yellow-legged gull, Milvus migrans-black kite, Milvus milvus-red kite, Ciconia ciconia-white stork, Sturnus unicolor-spotless starling, Aquila chrysaetos-golden eagle, Cuculus canorus-common cuckoo, Tyto alba-barn owl). Fifteen isolates harbored ESBL or pAmpC-encoding genes (number of isolates): bla SHV-12 (9), bla CTX-M-1 (3), bla CTX-M-14 (2), and bla CMY-2 (1). The last CTX(R) isolate presented a -42-point-mutation in the chromosomal ampC promoter. Eleven out of 15 ESBL/pAmpC E. coli isolates were multiresistant (most common resistance phenotype: β-lactams-quinolones-tetracycline-sulfamethoxazole/trimethoprim). A plasmid-mediated quinolone resistance determinant (qnrS1) was identified in one E. coli from a barn owl. High genetic diversity was observed among ESBL/pAmpC E. coli isolates, with 12 different sequence types (STs), including several strains of STs frequently detected among human clinical isolates (ST38/D, ST131/B2, ST155/B1, ST10/A). The ST131 isolate belonged to the emergent ciprofloxacin-resistant H30R subclone. This study reveals a high percentage of bird as carriers of ESBL/pAmpC E. coli isolates in Spain, highlighting the elevated rate among storks, kites, and vultures. Wild birds can contribute to the global spread of ESBL/pAmpC-producing E. coli in natural ecosystems.

  16. Transport of Escherichia coli in saturated porous media

    NARCIS (Netherlands)

    Foppen, J.W.A.

    2007-01-01

    Over de manier waarop de bacterie en tevens meest bekende fecale indicator soort Escherichia coli getransporteerd wordt in grondwater is relatief weinig bekend. In deze studie wordt de verwijdering van E. coli uit grondwater ten gevolge van E. coli - sediment interacties bestudeerd en modelmatig

  17. Transport of Escherichia coli in saturated porous media

    NARCIS (Netherlands)

    Foppen, J.W.A.

    2007-01-01

    Over de manier waarop de bacterie en tevens meest bekende fecale indicator soort Escherichia coli getransporteerd wordt in grondwater is relatief weinig bekend. In deze studie wordt de verwijdering van E. coli uit grondwater ten gevolge van E. coli - sediment interacties bestudeerd en modelmatig ge

  18. WGS accurately predicts antimicrobial resistance in Escherichia coli

    Science.gov (United States)

    Objectives: To determine the effectiveness of whole-genome sequencing (WGS) in identifying resistance genotypes of multidrug-resistant Escherichia coli (E. coli) and whether these correlate with observed phenotypes. Methods: Seventy-six E. coli strains were isolated from farm cattle and measured f...

  19. Transport of Escherichia coli in saturated porous media

    NARCIS (Netherlands)

    Foppen, J.W.A.

    2007-01-01

    Over de manier waarop de bacterie en tevens meest bekende fecale indicator soort Escherichia coli getransporteerd wordt in grondwater is relatief weinig bekend. In deze studie wordt de verwijdering van E. coli uit grondwater ten gevolge van E. coli - sediment interacties bestudeerd en modelmatig ge

  20. Diarrheagenic Escherichia coli Markers and Phenotypes among Fecal E. coli Isolates Collected from Nicaraguan Infants ▿

    OpenAIRE

    Reyes, Daniel; Vilchez, Samuel; Paniagua, Margarita; Colque-Navarro, Patricia; Weintraub, Andrej; Möllby, Roland; Kühn, Inger

    2010-01-01

    We analyzed the prevalence of diarrheagenic Escherichia coli (DEC) markers and common phenotypes in 2,164 E. coli isolates from 282 DEC-positive samples. Enteropathogenic E. coli (EPEC) and enteroaggregative E. coli (EAEC) were very diverse and were not correlated with diarrhea. Enterotoxigenic E. coli (ETEC) estA and enterohemorrhagic E. coli (EHEC) belonged to a few phenotypes and were significantly correlated with diarrhea.

  1. Diarrheagenic Escherichia coli Markers and Phenotypes among Fecal E. coli Isolates Collected from Nicaraguan Infants ▿

    OpenAIRE

    2010-01-01

    We analyzed the prevalence of diarrheagenic Escherichia coli (DEC) markers and common phenotypes in 2,164 E. coli isolates from 282 DEC-positive samples. Enteropathogenic E. coli (EPEC) and enteroaggregative E. coli (EAEC) were very diverse and were not correlated with diarrhea. Enterotoxigenic E. coli (ETEC) estA and enterohemorrhagic E. coli (EHEC) belonged to a few phenotypes and were significantly correlated with diarrhea.

  2. Analysis of plasmid-mediated multidrug resistance in Escherichia coli and Klebsiella oxytoca isolates from clinical specimens in Japan.

    Science.gov (United States)

    Ode, Takashi; Saito, Ryoichi; Kumita, Wakako; Sato, Kenya; Okugawa, Shu; Moriya, Kyoji; Koike, Kazuhiko; Okamura, Noboru

    2009-10-01

    This study investigated the relationship of plasmid-mediated quinolone resistance (PMQR) and aminoglycoside resistance among oxyimino-cephalosporin-resistant Escherichia coli (n=46) and Klebsiella oxytoca (n=28) clinical isolates in Japan. Seventy-three isolates appeared to produce an extended-spectrum beta-lactamase (ESBL) and one K. oxytoca isolate produced IMP-1 metallo-beta-lactamase (MBL). Polymerase chain reaction (PCR) and sequencing confirmed that eight CTX-M-9/SHV-12-producing isolates, one IMP-1-producing K. oxytoca isolate, and six ESBL-positive E. coli isolates respectively possessed PMQR genes qnrA1, qnrB6, and aac(6')-Ib-cr. All qnr-positive isolates also carried either aac(6')-Ib or aac(6')-IIc aminoglycoside acetyltransferase genes. Resistance determinants to beta-lactams, quinolones and aminoglycosides were co-transferred with a plasmid of ca. 140 kb. The qnrA1 gene was located downstream of insertion sequence ISCR1 in complex class 1 integrons. A novel qnrA1-carrying class 1 integron with the cassette arrangement aac(6')-IIc-aadA2 as well as a unique class 1 integron with bla(IMP-1)-aac(6')-IIc cassettes on the plasmid carrying qnrB6 were found in K. oxytoca isolates. We describe the identification of qnrB6 and aac(6')-Ib-cr and the close association of qnr with aac(6')-Ib and aac(6')-IIc for the first time in clinical isolates producing ESBL or MBL in Japan.

  3. Initiation of Replication in Escherichia coli

    DEFF Research Database (Denmark)

    Frimodt-Møller, Jakob

    The circular chromosome of Escherichia coli is replicated by two replisomes assembled at the unique origin and moving in the opposite direction until they meet in the less well defined terminus. The key protein in initiation of replication, DnaA, facilitates the unwinding of double-stranded DNA...... to single-stranded DNA in oriC. Although DnaA is able to bind both ADP and ATP, DnaA is only active in initiation when bound to ATP. Although initiation of replication, and the regulation of this, is thoroughly investigated it is still not fully understood. The overall aim of the thesis was to investigate...... the regulation of initiation, the effect on the cell when regulation fails, and if regulation was interlinked to chromosomal organization. This thesis uncovers that there exists a subtle balance between chromosome replication and reactive oxygen species (ROS) inflicted DNA damage. Thus, failure in regulation...

  4. The eclipse period of Escherichia coli

    DEFF Research Database (Denmark)

    von Freiesleben, Ulrik; Krekling, Martin A.; Hansen, Flemming G.

    2000-01-01

    The minimal time between successive initiations on the same origin (the eclipse) in Escherichia coli was determined to be approximately 25-30 min. An inverse relationship was found between the length of the eclipse and the amount of Dam methyltransferase in the cell, indicating that the eclipse...... corresponds to the period of origin hemimethylation. The SeqA protein was absolutely required for the eclipse, and DnaA titration studies suggested that the SeqA protein prevented the binding of multiple DnaA molecules on oriC (initial complex formation). No correlation between the amount of SeqA and eclipse...... length was revealed, but increased SeqA levels affected chromosome partitioning and/or cell division. This was corroborated further by an aberrant nucleoid distribution in SeqA-deficient cells. We suggest that the SeqA protein's role in maintaining the eclipse is tied to a function in chromosome...

  5. Genetic profiles of fluoroquinolone-resistant Escherichia coli isolates obtained from patients with cystitis: phylogeny, virulence factors, PAIusp subtypes, and mutation patterns.

    Science.gov (United States)

    Takahashi, Akira; Muratani, Tetsuro; Yasuda, Mitsuru; Takahashi, Satoshi; Monden, Koichi; Ishikawa, Kiyohito; Kiyota, Hiroshi; Arakawa, Soichi; Matsumoto, Tetsuro; Shima, Hiroki; Kurazono, Hisao; Yamamoto, Shingo

    2009-03-01

    The low virulence of quinolone- and fluoroquinolone-resistant Escherichia coli strains is known, although the reasons for this remain unclear. We surveyed the mutation patterns of quinolone resistance determining regions (QRDRs), phylogenetic distribution, prevalence of 18 urovirulence genes, and PAIusp subtypes in 89 fluoroquinolone-resistant E. coli (FQREC) isolates obtained from patients with cystitis and compared them with those of their fluoroquinolone-susceptible counterparts (FQSEC). Phylogenetic group B2 was significantly less prevalent in FQREC than in FQSEC (49% versus 78%; P=0.0138), but it still dominated, followed by phylogroup D (35%), in FQREC. When the prevalences of virulence factor (VF) genes were compared between FQREC and FQSEC, sfa/foc, cnf1, hly, kpsMT, ompT, ibeA, usp, and iroN showed significantly lower prevalences in FQREC than in FQSEC (1.1% versus 24% [Presistance, e.g., mutations in QRDRs, might be a specific event in limited strains, such as those that possess PAIusp subtype 2a in phylogroup B2.

  6. Differentiation in quinolone resistance by virulence genotype in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Melissa Agnello

    Full Text Available Pseudomonas aeruginosa is a leading pathogen that has become increasingly resistant to the fluoroquinolone antibiotics due to widespread prescribing. Adverse outcomes have been shown for patients infected with fluoroquinolone-resistant strains. The type III secretion system (TTSS is a major virulence determinant during acute infections through the injection of effector toxins into host cells. Most strains exhibit a unique TTSS virulence genotype defined by the presence of either exoS or exoU gene encoding two of the effector toxins, ExoS and ExoU, respectively. Specific TTSS effector genotype has been shown previously to differentially impact virulence in pneumonia. In this study, we examined the relationship between TTSS effector genotype and fluoroquinolone resistance mechanisms in a collection of 270 respiratory isolates. We found that a higher proportion of exoU+ strains were fluoroquinolone-resistant compared to exoS+ strains (63% vs 49%, p = 0.03 despite its lower overall prevalence (38% exoU+ vs 56% exoS+. Results from sequencing the quinolone resistance determining regions (QRDRs of the 4 target genes (gyrA, gyrB, parC, parE indicated that strains containing the exoU gene were more likely to acquire ≥ 2 mutations than exoS+ strains at MICs ≤ 8 µg/ml (13% vs none and twice as likely to have mutations in both gyrA and parC than exoS+ strains (48% vs 24% p = 0.0439. Our findings indicate that P. aeruginosa strains differentially develop resistance-conferring mutations that correlate with TTSS effector genotype and the more virulent exoU+ subpopulation. Differences in mutational processes by virulence genotype that were observed suggest co-evolution of resistance and virulence traits favoring a more virulent genotype in the quinolone-rich clinical environment.

  7. Escherichia coli in chronic inflammatory bowel diseases: An update on adherent invasive Escherichia coli pathogenicity

    Institute of Scientific and Technical Information of China (English)

    Margarita; Martinez-Medina; Librado; Jesus; Garcia-Gil

    2014-01-01

    Escherichia coli(E. coli), and particularly the adherent invasive E. coli(AIEC) pathotype, has been increasingly implicated in the ethiopathogenesis of Crohn’s disease(CD). E. coli strains with similar pathogenic features to AIEC have been associated with other intestinal disorders such as ulcerative colitis, colorectal cancer, and coeliac disease, but AIEC prevalence in these diseases remains largely unexplored. Since AIEC was described one decade ago, substantial progress has been made in deciphering its mechanisms of pathogenicity. However, the molecular bases that characterize the phenotypic properties of this pathotype are still not well resolved. A review of studies focused on E. coli populations in inflammatory bowel disease(IBD) is presented here and we discuss about the putative role of this species on each IBD subtype. Given the relevance of AIEC in CD pathogenesis, we present the latest research findings concerning AIEC host-microbe interactions and pathogenicity. We also review the existing data regarding the prevalence and abundance of AIEC in CD and its association with other intestinal diseases from humans and animals, in order to discuss the AIEC disease- and hostspecificity. Finally, we highlight the fact that dietarycomponents frequently found in industrialized countries may enhance AIEC colonization in the gut, which merits further investigation and the implementation of preventative measures.

  8. Escherichia coli biofilms: Accepting the therapeutic challenges

    Directory of Open Access Journals (Sweden)

    Trupti Bajpai

    2016-01-01

    Full Text Available Background: Urinary tract infections (UTI′s are a major public health concern globally. Recurrent UTI′s that are predominantly caused by uropathogenic Escherichia coli′s forms biofilm that is an intracellular, structured bacterial community, enclosed in a self-produced matrix, adherent to an inert, or living surface. Biofilm physiology is characterized by increased tolerance to stress, antibiotics, and immunological defenses, which is at the origin of their resilience in most medical and industrial settings. Materials and Methods: The present prospective study was carried out from December 2013 to May 2014 in the Department of Microbiology of a Teaching Tertiary Care hospital located in central India. A total of 100 consecutive, nonrepetitive E. coli isolates were subjected to biofilm formation study by Christensen′s tube adherence method. All the isolates were also subjected to antimicrobial susceptibility testing by Kirby-Bauer disc diffusion method in accordance with the Clinical Laboratory Standard Institute 2013 guidelines. Results and Discussion: Out of the 100 E. coli isolates studied, 62 (62% were positive for biofilm formation. High percentage of resistance was detected in isolates among the male inpatient group. Overall drug resistance was found to be very high among both biofilm as well as nonbiofilm forming isolates indicating excessive drug resistance among both community and hospital organisms. Conclusion: A greater understanding of the nature of biofilm organisms in chronic UTI′s would help in the development of novel and more effective treatments for these problematic diseases.

  9. Expanding ester biosynthesis in Escherichia coli.

    Science.gov (United States)

    Rodriguez, Gabriel M; Tashiro, Yohei; Atsumi, Shota

    2014-04-01

    To expand the capabilities of whole-cell biocatalysis, we have engineered Escherichia coli to produce various esters. The alcohol O-acyltransferase (ATF) class of enzyme uses acyl-CoA units for ester formation. The release of free CoA upon esterification with an alcohol provides the free energy to facilitate ester formation. The diversity of CoA molecules found in nature in combination with various alcohol biosynthetic pathways allows for the biosynthesis of a multitude of esters. Small to medium volatile esters have extensive applications in the flavor, fragrance, cosmetic, solvent, paint and coating industries. The present work enables the production of these compounds by designing several ester pathways in E. coli. The engineered pathways generated acetate esters of ethyl, propyl, isobutyl, 2-methyl-1-butyl, 3-methyl-1-butyl and 2-phenylethyl alcohols. In particular, we achieved high-level production of isobutyl acetate from glucose (17.2 g l(-1)). This strategy was expanded to realize pathways for tetradecyl acetate and several isobutyrate esters.

  10. The crystal structure Escherichia coli Spy.

    Science.gov (United States)

    Kwon, Eunju; Kim, Dong Young; Gross, Carol A; Gross, John D; Kim, Kyeong Kyu

    2010-11-01

    Escherichia coli spheroplast protein y (EcSpy) is a small periplasmic protein that is homologous with CpxP, an inhibitor of the extracytoplasmic stress response. Stress conditions such as spheroplast formation induce the expression of Spy via the Cpx or the Bae two-component systems in E. coli, though the function of Spy is unknown. Here, we report the crystal structure of EcSpy, which reveals a long kinked hairpin-like structure of four α-helices that form an antiparallel dimer. The dimer contains a curved oval shape with a highly positively charged concave surface that may function as a ligand binding site. Sequence analysis reveals that Spy is highly conserved over the Enterobacteriaceae family. Notably, three conserved regions that contain identical residues and two LTxxQ motifs are placed at the horizontal end of the dimer structure, stabilizing the overall fold. CpxP also contains the conserved sequence motifs and has a predicted secondary structure similar to Spy, suggesting that Spy and CpxP likely share the same fold.

  11. Independence of replisomes in Escherichia coli chromosomalreplication

    Energy Technology Data Exchange (ETDEWEB)

    Breier, Adam M.; Weier, Heinz-Ulrich G.; Cozzarelli, Nicholas R.

    2005-03-13

    In Escherichia coli DNA replication is carried out by the coordinated action of the proteins within a replisome. After replication initiation, the two bidirectionally oriented replisomes from a single origin are colocalized into higher-order structures termed replication factories. The factory model postulated that the two replisomes are also functionally coupled. We tested this hypothesis by using DNA combing and whole-genome microarrays. Nascent DNA surrounding oriC in single, combed chromosomes showed instead that one replisome, usually the leftward one, was significantly ahead of the other 70% of the time. We next used microarrays to follow replication throughout the genome by measuring DNA copy number. We found in multiple E. coli strains that the replisomes are independent, with the leftward replisome ahead of the rightward one. The size of the bias was strain-specific, varying from 50 to 130 kb in the array results. When we artificially blocked one replisome, the other continued unabated, again demonstrating independence. We suggest an improved version of the factory model that retains the advantages of threading DNA through colocalized replisomes at about equal rates, but allows the cell flexibility to overcome obstacles encountered during elongation.

  12. Biosynthesis of ethylene glycol in Escherichia coli.

    Science.gov (United States)

    Liu, Huaiwei; Ramos, Kristine Rose M; Valdehuesa, Kris Niño G; Nisola, Grace M; Lee, Won-Keun; Chung, Wook-Jin

    2013-04-01

    Ethylene glycol (EG) is an important platform chemical with steadily expanding global demand. Its commercial production is currently limited to fossil resources; no biosynthesis route has been delineated. Herein, a biosynthesis route for EG production from D-xylose is reported. This route consists of four steps: D-xylose → D-xylonate → 2-dehydro-3-deoxy-D-pentonate → glycoaldehyde → EG. Respective enzymes, D-xylose dehydrogenase, D-xylonate dehydratase, 2-dehydro-3-deoxy-D-pentonate aldolase, and glycoaldehyde reductase, were assembled. The route was implemented in a metabolically engineered Escherichia coli, in which the D-xylose → D-xylulose reaction was prevented by disrupting the D-xylose isomerase gene. The most efficient construct produced 11.7 g L(-1) of EG from 40.0 g L(-1) of D-xylose. Glycolate is a carbon-competing by-product during EG production in E. coli; blockage of glycoaldehyde → glycolate reaction was also performed by disrupting the gene encoding aldehyde dehydrogenase, but from this approach, EG productivity was not improved but rather led to D-xylonate accumulation. To channel more carbon flux towards EG than the glycolate pathway, further systematic metabolic engineering and fermentation optimization studies are still required to improve EG productivity.

  13. First description of OXA-48-producing Escherichia coli and the pandemic clone ST131 from patients hospitalised at a military hospital in Algeria.

    Science.gov (United States)

    Agabou, A; Pantel, A; Ouchenane, Z; Lezzar, N; Khemissi, S; Satta, D; Sotto, A; Lavigne, J-P

    2014-09-01

    The aim of the study was to assess the frequency and diversity of carbapenemases and extended-spectrum β-lactamases (ESBL) produced by Escherichia coli isolates from patients hospitalised in the Regional Military Hospital of Constantine (Algeria). E. coli isolates were collected over a 2-year period from patients presenting E. coli infections. Strains with reduced susceptibility to ertapenem and/or positive for ESBL were characterised with regard to antibiotic resistance, bla genes, phylogenetic groups, O25 serotyping, quinolone resistance, repetitive sequence-based polymerase chain reaction (rep-PCR) profiles and multi-locus sequence typing (MLST). Of the 448 isolated E. coli, 94 (20.9 %) were multidrug-resistant. One of them (1.1 %) produced a bla OXA-48 and was identified as a B1 ST5 strain. The transposon bearing this gene was Tn1999.2. This strain was isolated from a patient coming from a border province with Tunisia, where this carbapenemase is endemic. In addition, 84 (18.8 %) isolates among them produced an ESBL with predominance (97.6 %) of bla CTX-M-15, which was coupled with qnr genes in 10.9 %. ESBL-producing strains were mainly detected in phylogroups D and A. They displayed 20 rep-PCR profiles and all the clonally related isolates were of the same sequence type (ST). Ten strains (9.4 %) belonged to the pandemic clone ST131. This study describes for the first time the presence of OXA-48-producing E. coli and the emergence of the intercontinental ST131 bla CTX-15-producing E. coli strains in Algeria.

  14. Molecular characterisation of extended-spectrum β-lactamase- and plasmid AmpC-producing Escherichia coli strains isolated from broilers in Béjaïa, Algeria.

    Science.gov (United States)

    Belmahdi, Mohamed; Bakour, Sofiane; Al Bayssari, Charbel; Touati, Abdelaziz; Rolain, Jean-Marc

    2016-09-01

    This study aimed to characterise the molecular support of antibiotic resistance in expanded-spectrum cephalosporin (ESC)-resistant Escherichia coli isolates recovered from healthy broilers in Béjaïa, northeast Algeria. A total of 61 intestinal swabs from slaughtered broilers from four regions in Béjaïa locality, Algeria, were collected between February and April 2014, from which 20 ESC-resistant E. coli strains were isolated. Escherichia coli isolates were identified by classical biochemical and MALDI-TOF methods. Antibiotic susceptibility testing was performed using disk diffusion and Etest methods. Screening for β-lactamases, aminoglycoside-modifying enzyme (AME)-encoding genes and qnr determinants was performed by PCR and sequencing. Clonal relatedness was determined using molecular typing by multilocus sequence typing (MLST). Antibiotic susceptibility testing revealed that the isolates showed high rates of resistance (>90%) to amoxicillin, amoxicillin/clavulanic acid, piperacillin/tazobactam, aztreonam, ceftazidime, streptomycin, tobramycin, nalidixic acid and ciprofloxacin. Low rates of resistance were observed for kanamycin (35%), amikacin (30%), cefoxitin (20%) and cefotaxime (15%). Molecular characterisation revealed that all of the isolates expressed the blaTEM-1 gene. Fourteen of them harboured the blaSHV-12 gene, two harboured the blaCTX-M-1 gene and four isolates harboured blaCMY-2. Screening for AME-encoding genes demonstrated that all isolates contained the aadA gene. In addition, qnrA was detected as the quinolone resistance determinant in 13 isolates. MLST revealed four known sequence types (STs), including ST744, ST38, ST1011 and ST2179, as well as one new sequence type (ST5086). Here we report the first study describing the clonal diversity of extended-spectrum β-lactamase (ESBL)- and plasmid AmpC-producing E. coli isolated from healthy broilers in Algeria.

  15. The extracellular RNA complement of Escherichia coli.

    Science.gov (United States)

    Ghosal, Anubrata; Upadhyaya, Bimal Babu; Fritz, Joëlle V; Heintz-Buschart, Anna; Desai, Mahesh S; Yusuf, Dilmurat; Huang, David; Baumuratov, Aidos; Wang, Kai; Galas, David; Wilmes, Paul

    2015-01-21

    The secretion of biomolecules into the extracellular milieu is a common and well-conserved phenomenon in biology. In bacteria, secreted biomolecules are not only involved in intra-species communication but they also play roles in inter-kingdom exchanges and pathogenicity. To date, released products, such as small molecules, DNA, peptides, and proteins, have been well studied in bacteria. However, the bacterial extracellular RNA complement has so far not been comprehensively characterized. Here, we have analyzed, using a combination of physical characterization and high-throughput sequencing, the extracellular RNA complement of both outer membrane vesicle (OMV)-associated and OMV-free RNA of the enteric Gram-negative model bacterium Escherichia coli K-12 substrain MG1655 and have compared it to its intracellular RNA complement. Our results demonstrate that a large part of the extracellular RNA complement is in the size range between 15 and 40 nucleotides and is derived from specific intracellular RNAs. Furthermore, RNA is associated with OMVs and the relative abundances of RNA biotypes in the intracellular, OMV and OMV-free fractions are distinct. Apart from rRNA fragments, a significant portion of the extracellular RNA complement is composed of specific cleavage products of functionally important structural noncoding RNAs, including tRNAs, 4.5S RNA, 6S RNA, and tmRNA. In addition, the extracellular RNA pool includes RNA biotypes from cryptic prophages, intergenic, and coding regions, of which some are so far uncharacterised, for example, transcripts mapping to the fimA-fimL and ves-spy intergenic regions. Our study provides the first detailed characterization of the extracellular RNA complement of the enteric model bacterium E. coli. Analogous to findings in eukaryotes, our results suggest the selective export of specific RNA biotypes by E. coli, which in turn indicates a potential role for extracellular bacterial RNAs in intercellular communication. © 2015 The

  16. Escherichia coli Pathotypes Occupy Distinct Niches in the Mouse Intestine

    OpenAIRE

    Jessica P Meador; Caldwell, Matthew E.; Cohen, Paul S.; Conway, Tyrrell

    2014-01-01

    Since the first step of the infection process is colonization of the host, it is important to understand how Escherichia coli pathogens successfully colonize the intestine. We previously showed that enterohemorrhagic O157:H7 strain E. coli EDL933 colonizes a niche in the streptomycin-treated mouse intestine that is distinct from that of human commensal strains, which explains how E. coli EDL933 overcomes colonization resistance imparted by some, but not all, commensal E. coli strains. Here we...

  17. General considerations regarding the infections with the Escherichia coli pathogen

    Directory of Open Access Journals (Sweden)

    Marius Necşulescu

    2017-04-01

    Full Text Available Escherichia coli is the species of the genus Escherichia with the greatest epidemiological impact. Escherichia coli infections are found mainly in places with poor hygiene; the infants with ages between 1 and 3 years old are included in the category with the highest risk. It is a "fecal-oral" transmission mechanism as a result of consumption of contaminated food or water, or by "dirty hands". The foods most commonly implicated in the transmission of the infection are unpasteurized milk and milk products, beef, especially the one insufficiently cooked, unpasteurized fruit juice, lettuce and insufficiently washed vegetables. The disease has been reported worldwide, being described numerous episodes of infection with Escherichia coli that caused multiple illnesses and deaths. Escherichia coli has three types of antigens: antigen "O" (somatic, antigen "H" (flagella and antigen "K" (capsular. Clinical manifestations are present in the form of non-specific diarrhea, a dysentery form of enteritis, choleriform enteritis, hemorrhagic colitis and hemolytic uremic syndrome (HUS. The Escherichia coli infection diagnosis is made by identifying the etiologic agent and/or by highlighting the VTI toxin in the feces. The treatment consists in precautionary antibiotherapy, hydrodynamics and electrolyte rebalancing, blood transfusions and dialysis, if in the case of renal failure. The prevention of infections with Escherichia coli is achieved by personal hygiene, food hygiene and work hygiene.

  18. Antimicrobial resistance, virulence factors and genetic diversity of Escherichia coli isolates from household water supply in Dhaka, Bangladesh.

    Directory of Open Access Journals (Sweden)

    Prabhat Kumar Talukdar

    Full Text Available BACKGROUND: Unsafe water supplies continue to raise public health concerns, especially in urban areas in low resource countries. To understand the extent of public health risk attributed to supply water in Dhaka city, Bangladesh, Escherichia coli isolated from tap water samples collected from different locations of the city were characterized for their antibiotic resistance, pathogenic properties and genetic diversity. METHODOLOGY/PRINCIPAL FINDINGS: A total of 233 E. coli isolates obtained from 175 tap water samples were analysed for susceptibility to 16 different antibiotics and for the presence of genes associated with virulence and antibiotic resistance. Nearly 36% (n = 84 of the isolates were multi-drug(≥ 3 classes of antibiotics resistant (MDR and 26% (n = 22 of these were positive for extended spectrum β-lactamase (ESBL. Of the 22 ESBL-producers, 20 were positive for bla CTX-M-15, 7 for bla OXA-1-group (all had bla OXA-47 and 2 for bla CMY-2. Quinolone resistance genes, qnrS and qnrB were detected in 6 and 2 isolates, respectively. Around 7% (n = 16 of the isolates carried virulence gene(s characteristic of pathogenic E. coli; 11 of these contained lt and/or st and thus belonged to enterotoxigenic E. coli and 5 contained bfp and eae and thus belonged to enteropathogenic E. coli. All MDR isolates carried multiple plasmids (2 to 8 of varying sizes ranging from 1.2 to >120 MDa. Ampicillin and ceftriaxone resistance were co-transferred in conjugative plasmids of 70 to 100 MDa in size, while ampicillin, trimethoprim-sulfamethoxazole and tetracycline resistance were co-transferred in conjugative plasmids of 50 to 90 MDa. Pulsed-field gel electrophoresis analysis revealed diverse genetic fingerprints of pathogenic isolates. SIGNIFICANCE: Multi-drug resistant E. coli are wide spread in public water supply in Dhaka city, Bangladesh. Transmission of resistant bacteria and plasmids through supply water pose serious threats to public health in

  19. Emerging Escherichia coli O25b/ST131 clone predicts treatment failure in urinary tract infections.

    Science.gov (United States)

    Can, Fusun; Azap, Ozlem Kurt; Seref, Ceren; Ispir, Pelin; Arslan, Hande; Ergonul, Onder

    2015-02-15

    We described the clinical predictive role of emerging Escherichia coli O25b/sequence type 131 (ST131) in treatment failure of urinary tract infection. In this prospective observational cohort study, the outpatients with acute cystitis with isolation of E. coli in their urine cultures were assessed. All the patients were followed up for clinical cure after 10 days of treatment. Detection of the E. coli O25:H4/ST131 clone was performed by multiplex polymerase chain reaction (PCR) for phylogroup typing and using PCR with primers for O25b rfb and allele 3 of the pabB gene. In a cohort of patients with diagnosis of acute urinary cystitis, 294 patients whose urine cultures were positive with a growth of >10(4) colony-forming units/mL of E. coli were included in the study. In empiric therapy, ciprofloxacin was the first choice of drug (27%), followed by phosphomycin (23%), trimethoprim-sulfamethoxazole (TMP-SMX) (9%), and cefuroxime (7%). The resistance rate was 39% against ciprofloxacin, 44% against TMP-SMX, and 25% against cefuroxime. Thirty-five of 294 (12%) isolates were typed under the O25/ST131 clone. The clinical cure rate was 85% after the treatment. In multivariate analysis, detection of the O25/ST131 clone (odds ratio [OR], 4; 95% confidence interval [CI], 1.51-10.93; P = .005) and diabetes mellitus (OR, 2.1; 95% CI, .99-4.79; P = .05) were found to be significant risk factors for the treatment failure. In another multivariate analysis performed among quinolone-resistant isolates, treatment failure was 3 times more common among the patients who were infected with ST131 E. coli (OR, 3; 95% CI, 1.27-7.4; P = .012). In urinary tract infections, the E. coli ST131 clone seems to be a consistent predictor of treatment failure. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. Dynamics of Escherichia coli Chromosome Segregation during Multifork Replication

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck; Youngren, Brenda; Hansen, Flemming G.

    2007-01-01

    Slowly growing Escherichia coli cells have a simple cell cycle, with replication and progressive segregation of the chromosome completed before cell division. In rapidly growing cells, initiation of replication occurs before the previous replication rounds are complete. At cell division...

  1. The incidence and antibiotics susceptibility of Escherichia coli O157 ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-02-22

    Feb 22, 2010 ... The incidence of Escherichia coli 0157: H7 was assessed in meat samples from .... of this product resulting from contamination with STEC, a zoonotic .... Adak GK, Longs SM, O'Briens SJ (2002) Trends in indigenous forborne.

  2. mcr-1 identified in Avian Pathogenic Escherichia coli (APEC)

    National Research Council Canada - National Science Library

    Nicolle Lima Barbieri; Daniel W Nielsen; Yvonne Wannemuehler; Tia Cavender; Ashraf Hussein; Shi-gan Yan; Lisa K Nolan; Catherine M Logue

    2017-01-01

    .... Here, we examined a collection (n = 980) of Avian Pathogenic Escherichia coli (APEC) isolated from poultry with colibacillosis from the US and internationally for the presence of mcr-1 and mcr-2, genes known to encode colistin resistance...

  3. Overexpression of vsr in Escherichia coli is mutagenic.

    Science.gov (United States)

    Doiron, K M; Viau, S; Koutroumanis, M; Cupples, C G

    1996-01-01

    Overexpression of vsr in Escherichia coli stimulates transition and frameshift mutations. The pattern of mutations suggests that mutagenesis is due to saturation or inactivation of dam-directed mismatch repair. PMID:8763960

  4. Norfloxacin resistance in a clinical isolate of Escherichia coli.

    OpenAIRE

    Aoyama, H; Sato, K; Kato, T.; Hirai, K; Mitsuhashi, S.

    1987-01-01

    Analysis of DNA gyrase supercoiling and of norfloxacin uptake in Escherichia coli GN14176, a moderately norfloxacin-resistant clinical isolate, indicated that resistance was associated with both an altered drug target and a reduction in drug uptake.

  5. Shigella strains are not clones of Escherichia coli but sister species in the genus Escherichia.

    Science.gov (United States)

    Zuo, Guanghong; Xu, Zhao; Hao, Bailin

    2013-02-01

    Shigella species and Escherichia coli are closely related organisms. Early phenotyping experiments and several recent molecular studies put Shigella within the species E. coli. However, the whole-genome-based, alignment-free and parameter-free CVTree approach shows convincingly that four established Shigella species, Shigella boydii, Shigella sonnei, Shigella felxneri and Shigella dysenteriae, are distinct from E. coli strains, and form sister species to E. coli within the genus Escherichia. In view of the overall success and high resolution power of the CVTree approach, this result should be taken seriously. We hope that the present report may promote further in-depth study of the Shigella-E. coli relationship.

  6. ENERGY REQUIREMENT FOR THYMINELESS DEATH IN CELLS OF ESCHERICHIA COLI.

    Science.gov (United States)

    FREIFELDER, D; MAALOE, O

    1964-10-01

    Freifelder, David (University of California, Berkeley), and Ole Maaløe. Energy requirement for thymineless death in cells of Escherichia coli. J. Bacteriol. 88:987-990. 1964.-Thymineless death in thymine-requiring Escherichia coli is arrested immediately and reversibly by nitrogenation if the bacterial population is growing in a medium containing a carbon source that can only be metabolized aerobically. The mechanism of death, therefore, involves a metabolic process.

  7. Plasmid-Mediated Colistin Resistance Gene mcr-1 in an Escherichia coli ST10 Bloodstream Isolate in the Sultanate of Oman.

    Science.gov (United States)

    Mohsin, Jalila; Pál, Tibor; Petersen, Jorgen Eskild; Darwish, Dania; Ghazawi, Akela; Ashraf, Tanveer; Sonnevend, Agnes

    2017-08-11

    To identify plasmid-mediated colistin resistance in clinical Enterobacteriaceae isolates in Oman, where this resistance mechanism has not been encountered yet. Twenty-two colistin-resistant Enterobacteriaceae clinical isolates collected between July 2014 and June 2016 in a tertiary care hospital in Muscat were screened by PCR for the mcr-1 and mcr-2 genes. The strain identified as mcr-1 positive was genotyped and its antibiotic susceptibility was established. The mcr-1 containing plasmid was mobilized into Escherichia coli K-12 and its sequence was determined. A single E. coli isolate (OM97) carrying mcr-1 gene was identified, while no strains carrying the mcr-2 gene was found. E. coli OM97 was isolated in June 2016 from blood culture of a male patient with multiple comorbidities. It belonged to ST10. Beyond colistin, it was resistant to amoxicillin-clavulanic acid, piperacillin-tazobactam, amikacin, ciprofloxacin, tetracycline, and cotrimoxazole. The mcr-1 gene was located on a conjugative IncI2-type plasmid of 63722 bp size, which did not harbor any further resistance genes. The genetic surrounding of the mcr-1 gene lacked the ISApl1 element. Although colistin resistance caused by the mcr-1 gene is not common in our collection of clinical isolates, the occurrence of the plasmid-mediated colistin resistance in an E. coli ST10 strain is of concern as this clonal group was already shown to spread ESBL genes and quinolone resistance worldwide. It is especially worrisome that as the mcr-1 gene occurred in a non-ESBL, carbapenem-susceptible E. coli strain, current susceptibility testing algorithms may not detect its presence.

  8. Molecular and phylogenetic characterization of multidrug resistant extended spectrum beta-lactamase producing Escherichia coli isolated from poultry and cattle in Odisha, India.

    Science.gov (United States)

    Kar, Debasish; Bandyopadhyay, Samiran; Bhattacharyya, Debaraj; Samanta, Indranil; Mahanti, Achintya; Nanda, Pramod K; Mondal, Bimalendu; Dandapat, Premanshu; Das, Arun K; Dutta, Tapan K; Bandyopadhyay, Subhasish; Singh, Raj Kumar

    2015-01-01

    The present study was undertaken to determine the occurrence and characterization of extended spectrum beta-lactamase (ESBL) producing Escherichia coli isolated from cattle and poultry in Odisha, India. Of 316 E. coli isolated from 305 samples (170 fecal samples from poultry and 135 milk samples from cattle), a total of 18 E. coli isolates were confirmed as ESBL producers by combination disc method and ESBL E-test. The isolates were resistant to oxyimino cephalosporins and monobactam as revealed by disc diffusion assay and determination of minimum inhibitory concentration. Resistance against other antibiotics was frequently noted as well. Further, beta-lactamase genes viz., blaSHV, blaCTXM, blaTEM and blaampC were detected in 17, 13, 9 and 2 isolates, respectively in PCR. Of the 18 ESBL strains, 16 were positive for class I integron (int1), nine of them carried sulphonamide resistance gene (sul1) and one harbored quinolone resistance gene (qnrB). Virulence markers for extraintestinal pathogenic E. coli like astA, tsh and iucD were also present in 4, 3 and 3 isolates, respectively. All the PCR amplified products were cloned and subjected to sequencing for homology analysis and data were submitted to gene bank. Sequence analysis of the amplified variable regions of class 1 integron of four representative isolates revealed the presence of aadA2 and dfrA12 gene cassettes conferring resistance to aminoglycosides and trimethoprim, respectively. Most of the ESBL producing strains emerged as single lineage through phylogenetic analysis by RAPD and ERIC PCR. This is the first ever systemic study on multidrug resistant ESBL producing E. coli in food producing animals from India.

  9. Resistance Pattern and Molecular Characterization of Enterotoxigenic Escherichia coli (ETEC) Strains Isolated in Bangladesh.

    Science.gov (United States)

    Begum, Yasmin A; Talukder, K A; Azmi, Ishrat J; Shahnaij, Mohammad; Sheikh, A; Sharmin, Salma; Svennerholm, A-M; Qadri, Firdausi

    2016-01-01

    Enterotoxigenic Escherichia coli (ETEC) is a common cause of bacterial infection leading to acute watery diarrhea in infants and young children as well as in travellers to ETEC endemic countries. Ciprofloxacin is a broad-spectrum antimicrobial agent nowadays used for the treatment of diarrhea. This study aimed to characterize ciprofloxacin resistant ETEC strains isolated from diarrheal patients in Bangladesh. A total of 8580 stool specimens from diarrheal patients attending the icddr,b Dhaka hospital was screened for ETEC between 2005 and 2009. PCR and Ganglioside GM1- Enzyme Linked Immuno sorbent Assay (ELISA) was used for detection of Heat labile (LT) and Heat stable (ST) toxins of ETEC. Antimicrobial susceptibilities for commonly used antibiotics and the minimum inhibitory concentration (MIC) of nalidixic acid, ciprofloxacin and azithromycin were examined. DNA sequencing of representative ciprofloxacin resistant strains was performed to analyze mutations of the quinolone resistance-determining region of gyrA, gyrB, parC and parE. PCR was used for the detection of qnr, a plasmid mediated ciprofloxacin resistance gene. Clonal variations among ciprofloxacin resistant (CipR) and ciprofloxacin susceptible (CipS) strains were determined by Pulsed-field gel electrophoresis (PFGE). Among 1067 (12%) ETEC isolates identified, 42% produced LT/ST, 28% ST and 30% LT alone. Forty nine percent (n = 523) of the ETEC strains expressed one or more of the 13 tested colonization factors (CFs) as determined by dot blot immunoassay. Antibiotic resistance of the ETEC strains was observed as follows: ampicillin 66%, azithromycin 27%, ciprofloxacin 27%, ceftriazone 13%, cotrimaxazole 46%, doxycycline 44%, erythromycin 96%, nalidixic acid 83%, norfloxacin 27%, streptomycin 48% and tetracycline 42%. Resistance to ciprofloxacin increased from 13% in 2005 to 34% in 2009. None of the strains was resistant to mecillinam. The MIC of the nalidixic acid and ciprofloxacin of representative Cip

  10. Resistance Pattern and Molecular Characterization of Enterotoxigenic Escherichia coli (ETEC Strains Isolated in Bangladesh.

    Directory of Open Access Journals (Sweden)

    Yasmin A Begum

    Full Text Available Enterotoxigenic Escherichia coli (ETEC is a common cause of bacterial infection leading to acute watery diarrhea in infants and young children as well as in travellers to ETEC endemic countries. Ciprofloxacin is a broad-spectrum antimicrobial agent nowadays used for the treatment of diarrhea. This study aimed to characterize ciprofloxacin resistant ETEC strains isolated from diarrheal patients in Bangladesh.A total of 8580 stool specimens from diarrheal patients attending the icddr,b Dhaka hospital was screened for ETEC between 2005 and 2009. PCR and Ganglioside GM1- Enzyme Linked Immuno sorbent Assay (ELISA was used for detection of Heat labile (LT and Heat stable (ST toxins of ETEC. Antimicrobial susceptibilities for commonly used antibiotics and the minimum inhibitory concentration (MIC of nalidixic acid, ciprofloxacin and azithromycin were examined. DNA sequencing of representative ciprofloxacin resistant strains was performed to analyze mutations of the quinolone resistance-determining region of gyrA, gyrB, parC and parE. PCR was used for the detection of qnr, a plasmid mediated ciprofloxacin resistance gene. Clonal variations among ciprofloxacin resistant (CipR and ciprofloxacin susceptible (CipS strains were determined by Pulsed-field gel electrophoresis (PFGE.Among 1067 (12% ETEC isolates identified, 42% produced LT/ST, 28% ST and 30% LT alone. Forty nine percent (n = 523 of the ETEC strains expressed one or more of the 13 tested colonization factors (CFs as determined by dot blot immunoassay. Antibiotic resistance of the ETEC strains was observed as follows: ampicillin 66%, azithromycin 27%, ciprofloxacin 27%, ceftriazone 13%, cotrimaxazole 46%, doxycycline 44%, erythromycin 96%, nalidixic acid 83%, norfloxacin 27%, streptomycin 48% and tetracycline 42%. Resistance to ciprofloxacin increased from 13% in 2005 to 34% in 2009. None of the strains was resistant to mecillinam. The MIC of the nalidixic acid and ciprofloxacin of representative

  11. Nanotextile membranes for bacteria Escherichia coli capturing

    Directory of Open Access Journals (Sweden)

    Jaroslav Lev

    2010-01-01

    Full Text Available The article describes an experimental study dealing with the possibility of nanotextile materials usa­ge for microbiologically contaminated water filtration. The aim of the study is to verify filtration ability of different nanotextile materials and evaluate the possibilities of practical usage. Good detention ability of these materials in the air filtration is the presumption for nanotextile to be used for bacteria filtration from a liquid. High nanotextile porosity with the nanotextile pores dimensions smaller than a bacteria size predicates the possibility of a successful usage of these materials. For the experiment were used materials made from electrospinning nanofibres under the label PA612, PUR1, PUR2 s PUR3 on the supporting unwoven textiles (viscose and PP. As a model simulation of the microbial contamination, bacteria Escherichia coli was chosen. Contaminated water was filtered during the overpressure activity of 105Pa on the input side of the filter from the mentioned material. After three-day incubation on the nutrient medium, cultures found in the samples before and after filtration were compared. In the filtrated water, bacteria E. coli were indicated, which did not verify the theoretical presumptions about an absolut bacteria detention. However, used materials caught at least 94% of bacteria in case of material PUR1 and up to 99,996% in case of material PUR2. These results predict the possibility of producing effective nanotextile filters for microbiologically contaminated water filtration.Recommendation: For the production of materials with better filtrating qualities, experiments need to be done, enabling better understanding of the bacteria detention mechanisms on the nanotextile material, and parameters of the used materials that influence the filtrating abilities need to be verified.

  12. Characterization of quinolone resistance in Salmonella enterica serovar Indiana from chickens in China.

    Science.gov (United States)

    Lu, Yan; Zhao, Hongyu; Liu, Yuqi; Zhou, Xuping; Wang, Jinyuan; Liu, Tiantian; Beier, Ross C; Hou, Xiaolin

    2015-03-01

    The aim of this study was to characterize the quinolone resistance of Salmonella enterica serovar Indiana isolated from chickens in China. A total of 293 Salmonella strains were isolated from chicken farms and slaughterhouses in Shandong province of China, and 130 (44.4%) were characterized as Salmonella enterica Indiana (chicken farms, n=52 strains; slaughter houses, n=78 strains). All isolate serotypes were tested with the Kauffmann-White classification system and examined for susceptibility to the quinolones: nalidixic acid, enrofloxacin, norfloxacin, and ciprofloxacin. The resistance of the Salmonella Indiana strains to nalidixic acid, enrofloxacin, norfloxacin, and ciprofloxacin were 100, 73.1, 71.2, and 82.7%, and 100, 59.0, 79.5, and 80.2%, respectively. Selected quinolone resistant strains were evaluated for mutations in genes (gyrA, gyrB, parC, and marA) by DNA sequencing. The gyrA mutation was found in all isolates, the parC mutation was only found in some isolates, and the gyrB and marA mutations were not observed. Quinolone resistance was evaluated in the representative isolates by screening for the quinolone resistance determinants, qnrA, qnrB, qnrS, qepA, and aac (6 ')-Ib-cr using PCR technology. The quinolone resistance determinants in Salmonella, qnrA, qnrB, qnrS, and qepA were negative by PCR, but aac(6 ')-Ib-cr had high detection rates of 90.4 and 96.2% in chicken farms and slaughterhouses, respectively. Salmonella Indiana containing the gyrA mutation was prevalent in farms and slaughterhouses and possessed a high frequency of the quinolone resistance determinant aac(6 ')-Ib-cr. These bacteria may have originated from the same source.

  13. Annual Surveillance Summary: Escherichia coli (E. coli) Infections in the Military Health System (MHS), 2016

    Science.gov (United States)

    2017-06-30

    Annual Surveillance Summary: Escherichia coli (E. coli) Infections in the Military Health System (MHS...and prevalence among all beneficiaries seeking care within the Military Health System (MHS). This report describes demographics, clinical...linked to assess descriptive and clinical factors related to E. coli. Health Level 7 (HL7)-formatted Composite Health Care System (CHCS) microbiology data

  14. Prevalence of plasmid-mediated quinolone resistance determinants among oxyiminocephalosporin-resistant Enterobacteriaceae in Argentina

    Directory of Open Access Journals (Sweden)

    Giovanna Rincon Cruz

    2013-11-01

    Full Text Available High quinolone resistance rates were observed among oxyiminocephalosporin-resistant enterobacteria. In the present study, we searched for the prevalence of plasmid-mediated quinolone resistance (PMQR genes within the 55 oxyiminocephalosporin-resistant enterobacteria collected in a previous survey. The main PMQR determinants were aac(6'-Ib-cr and qnrB, which had prevalence rates of 42.4% and 33.3%, respectively. The aac(6'-Ib-cr gene was more frequently found in CTX-M-15-producing isolates, while qnrB was homogeneously distributed among all CTX-M producers.

  15. Molecular characteristics of extended-spectrum β-lactamases in clinical isolates from Escherichia coli at a Japanese tertiary hospital.

    Science.gov (United States)

    Yano, Hisakazu; Uemura, Mina; Endo, Shiro; Kanamori, Hajime; Inomata, Shinya; Kakuta, Risako; Ichimura, Sadahiro; Ogawa, Miho; Shimojima, Masahiro; Ishibashi, Noriomi; Aoyagi, Tetsuji; Hatta, Masumitsu; Gu, Yoshiaki; Yamada, Mitsuhiro; Tokuda, Koichi; Kunishima, Hiroyuki; Kitagawa, Miho; Hirakata, Yoichi; Kaku, Mitsuo

    2013-01-01

    The prevalence of ESBL has been increasing worldwide. In this study, we investigated the molecular characteristics of ESBL among clinical isolates of Escherichia coli from a Japanese tertiary hospital. A total of 71 consecutive and nonduplicate clinical isolates of ESBL-positive E. coli collected at Tohoku University Hospital between January 2008 and March 2011 were studied. The antimicrobial susceptibility profile of these strains was determined. PCR and sequencing were performed to identify genes for β-lactamase (bla(TEM), bla(SHV), bla(OXA-1-like), and bla(CTX-M)) and plasmid-mediated quinolone resistance determinants (PMQR). The isolates were also analyzed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Of the 71 strains, 68 were positive for CTX-M, 28 were positive for TEM, four were positive for OXA-1, and one was positive for SHV. Sequencing revealed that CTX-M-14 was the most prevalent (31/71), followed by CTX-M-27 (21/71) and then CTX-M-15 (9/71). Of the 28 TEM-positive strains, one was TEM-10 and the rest were TEM-1. One SHV-positive strain was SHV-12. The 21 CTX-M-27-producing isolates were divided into 14 unique PFGE types, while the 9 CTX-M-15 producers were divided into 8 types. Based on MLST, 9 CTX-M-14 procedures, 19 CTX-M-27 procedures, and 8 CTX-M-15 producers belonged to ST131. Thirty-five (94.6%) of the 37 ST131 E. coli strains showed resistance to levofloxacin, which was a higher rate than among non-ST131 strains (63.6%). Among ESBL-producing isolates, one, two, and six possessed qnrB, qnrS, qepA, and aac(6')-Ib-cr, respectively. Of the 6 isolates with aac(6')-Ib-cr, 4 carried the CTX-M-15 gene. Our data suggest that CTX-M-15-producing E. coli ST131 has emerged as a worldwide pandemic clone, while CTX-M-27 (a variant of CTX-M-14) is also spreading among E. coli ST131 in Japan.

  16. Molecular characteristics of extended-spectrum β-lactamases in clinical isolates from Escherichia coli at a Japanese tertiary hospital.

    Directory of Open Access Journals (Sweden)

    Hisakazu Yano

    Full Text Available The prevalence of ESBL has been increasing worldwide. In this study, we investigated the molecular characteristics of ESBL among clinical isolates of Escherichia coli from a Japanese tertiary hospital. A total of 71 consecutive and nonduplicate clinical isolates of ESBL-positive E. coli collected at Tohoku University Hospital between January 2008 and March 2011 were studied. The antimicrobial susceptibility profile of these strains was determined. PCR and sequencing were performed to identify genes for β-lactamase (bla(TEM, bla(SHV, bla(OXA-1-like, and bla(CTX-M and plasmid-mediated quinolone resistance determinants (PMQR. The isolates were also analyzed by pulsed-field gel electrophoresis (PFGE and multilocus sequence typing (MLST. Of the 71 strains, 68 were positive for CTX-M, 28 were positive for TEM, four were positive for OXA-1, and one was positive for SHV. Sequencing revealed that CTX-M-14 was the most prevalent (31/71, followed by CTX-M-27 (21/71 and then CTX-M-15 (9/71. Of the 28 TEM-positive strains, one was TEM-10 and the rest were TEM-1. One SHV-positive strain was SHV-12. The 21 CTX-M-27-producing isolates were divided into 14 unique PFGE types, while the 9 CTX-M-15 producers were divided into 8 types. Based on MLST, 9 CTX-M-14 procedures, 19 CTX-M-27 procedures, and 8 CTX-M-15 producers belonged to ST131. Thirty-five (94.6% of the 37 ST131 E. coli strains showed resistance to levofloxacin, which was a higher rate than among non-ST131 strains (63.6%. Among ESBL-producing isolates, one, two, and six possessed qnrB, qnrS, qepA, and aac(6'-Ib-cr, respectively. Of the 6 isolates with aac(6'-Ib-cr, 4 carried the CTX-M-15 gene. Our data suggest that CTX-M-15-producing E. coli ST131 has emerged as a worldwide pandemic clone, while CTX-M-27 (a variant of CTX-M-14 is also spreading among E. coli ST131 in Japan.

  17. Completion of DNA replication in Escherichia coli.

    Science.gov (United States)

    Wendel, Brian M; Courcelle, Charmain T; Courcelle, Justin

    2014-11-18

    The mechanism by which cells recognize and complete replicated regions at their precise doubling point must be remarkably efficient, occurring thousands of times per cell division along the chromosomes of humans. However, this process remains poorly understood. Here we show that, in Escherichia coli, the completion of replication involves an enzymatic system that effectively counts pairs and limits cellular replication to its doubling point by allowing converging replication forks to transiently continue through the doubling point before the excess, over-replicated regions are incised, resected, and joined. Completion requires RecBCD and involves several proteins associated with repairing double-strand breaks including, ExoI, SbcDC, and RecG. However, unlike double-strand break repair, completion occurs independently of homologous recombination and RecA. In some bacterial viruses, the completion mechanism is specifically targeted for inactivation to allow over-replication to occur during lytic replication. The results suggest that a primary cause of genomic instabilities in many double-strand-break-repair mutants arises from an impaired ability to complete replication, independent from DNA damage.

  18. (ESBL)-producing Escherichia coli isolated from cl

    African Journals Online (AJOL)

    spectrum beta-lactamase (ESBL)-producing Escherichia coli isolated from clinical ... Methods: A total of 127 E. coli were collected from clinical samples in Kerman hospitals. The antibiotic ..... in Mexico and 26.1 % in Turkey [23,24]. These.

  19. Efficient expression of the yeast metallothionein gene in Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Berka, T.; Shatzman, A.; Zimmerman, J.; Strickler, J.; Rosenberg, M.

    1988-01-01

    The yeast metallothionein gene CUP1 was cloned into a bacterial expression system to achieve efficient, controlled expression of the stable, unprocessed protein product. The Escherichia coli-synthesized yeast metallothionein bound copper, cadmium, zinc, indicating that the protein was functional. Furthermore, E. coli cells expressing CUP1 acquired a new, inducible ability to selectively sequester heavy metal ions from the growth medium.

  20. Antimicrobial activity of peptidomimetics against multidrug-resistant Escherichia coli

    DEFF Research Database (Denmark)

    Jahnsen, Rasmus D; Frimodt-Møller, Niels; Franzyk, Henrik

    2012-01-01

    -lactamase-producing Escherichia coli was assessed by testing an array comprising different types of cationic peptidomimetics obtained by a general monomer-based solid-phase synthesis protocol. Most of the peptidomimetics possessed high to moderate activity toward multidrug-resistant E. coli as opposed to the corresponding...

  1. Characterization of enterohemorrhagic Escherichia coli on veal hides and carcasses

    Science.gov (United States)

    Enterohemorrhagic E. coli (EHEC) are Shiga toxin–producing Escherichia coli (STEC) associated with the most severe forms of foodborne illnesses. The United States Department of Agriculture (USDA) Food Safety Inspection Service (FSIS) has identified a higher percentage of non-O157 EHEC compared to E....

  2. Escherichia coli Eyelid Abscess in a Patient with Alcoholic Cirrhosis

    Directory of Open Access Journals (Sweden)

    Matthew Stratton

    2015-01-01

    Full Text Available Escherichia coli (E. coli is a rare cause of ocular infections and has not yet been reported as a cause of an ocular abscess. We describe the case of a 47-year-old woman with a history of alcoholic cirrhosis who presented with painful left lower eyelid swelling that did not improve with oral antibiotics. The abscess was drained and cultures were positive for E. coli. Patients with cirrhosis are at increased risk for developing E. coli bacterial infections, but to our knowledge this is the first case of an E. coli eyelid abscess reported in the literature.

  3. {sup 99m}Technetium labelled Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Diniz, S.O.F.; Cardoso, V.N. [Radioisotope Laboratory, Faculty of Pharmacy/UFMG, Belo Horizonte (Brazil); Resende, B.M.; Nunan, E.A. [Biological Control Laboratory, Faculty of Pharmacy/UFMG, Belo Horizonte (Brazil); Simal, C.J.R. [Laboratory Nuclear Medicine, Faculty of Medicine/UFMG, Belo Horizonte (Brazil)

    1999-07-01

    Samples of a culture of unlabeled Escherichia coli were incubated with different concentrations of stannous chloride for various time periods. {sup 99m}Tc (26.0 MBq) was added to each preparation and the results showed a labelling yield of 98% for E. coli. Since the bacterial viability of {sup 99m}Tc-E. coli and E. coli did not show any statistical differences, these results demonstrate that labelling of E. coli with {sup 99m}Tc does not modify the bacterial viability, and the radiolabelled bacteria may be a good model to study bacterial translocation.

  4. Identification of plasmid-mediated quinolone resistance qnr genes in multidrug-resistant Gram-negative bacteria from hospital wastewaters and receiving waters in the Jinan area, China.

    Science.gov (United States)

    Xia, Ruirui; Ren, Ye; Xu, Hai

    2013-12-01

    We investigated the prevalence of plasmid-mediated quinolone resistance (PMQR) qnr genes by the polymerase chain reaction (PCR) in antibiotic-resistant bacteria isolates collected from aquatic environments in Jinan during 2 years (2008.3-2009.11). Genes were identified to variant level by PCR restriction fragment length polymorphism analysis or sequencing. qnrA1, qnrB2, qnrB4, qnrB6, qnrB9, qnrS1, and the new qnrB variant qnrB26 were detected in 31 strains from six genera (Klebsiella spp., Escherichia coli, Enterobacter spp., Proteus spp., Shigella spp., and Citrobacter spp.), four of which contained double qnr genes. Other PMQR genes, aac(6')-Ib-cr and qepA, were found in 12 (38.7%) and 5 (16.1%) of 31 isolates, respectively; while qepA was found in Shigella spp. for the first time. Eight types of β-lactamase genes and eight other types of resistance genes were also present in the 31 qnr-positive isolates. The detection rate for five β-lactamase genes (blaTEM, blaCTX, ampR, blaDHA, and blaSHV) was >45%. Class 1 integrons and complex class 1 integrons were prevalent in these strains, which contained 15 different gene cassette arrays and 5 different insertion sequence common region 1 (ISCR1)-mediated downstream structures. qnrA1, qnrB2, and qnrB6 were present in three ISCR1-mediated downstream structures: qnrA1-ampR, sapA-like-qnrB2, and sdr-qnrB6. We also analyzed the horizontal transferability of PMQR genes and other resistance determinants. The qnr genes and some integrons and resistance genes from 18 (58.1%) of the 31 qnr-positive strains could be transferred to E. coli J53 Azi(R) or E. coli DH5α recipient strains using conjugation or transformation methods. The results showed that a high number of qnr genes were associated with other resistance genes in aquatic environments in Jinan. This suggests that we should avoid over-using antibiotics and monitor aquatic environments to control the spread of antibiotic resistance genes.

  5. Molecular Evolutionary Relationships of Enteroinvasive Escherichia coli and Shigella spp.

    OpenAIRE

    Lan, Ruiting; Alles, M. Chehani; Donohoe, Kathy; Marina B Martinez; Reeves, Peter R.

    2004-01-01

    Enteroinvasive Escherichia coli (EIEC), a distinctive pathogenic form of E. coli causing dysentery, is similar in many properties to bacteria placed in the four species of Shigella. Shigella has been separated as a genus but in fact comprises several clones of E. coli. The evolutionary relationships of 32 EIEC strains of 12 serotypes have been determined by sequencing of four housekeeping genes and two plasmid genes which were used previously to determine the relationships of Shigella strains...

  6. Findings of Escherichia coli and Enterococcus spp. in homemade cheese

    Directory of Open Access Journals (Sweden)

    Tambur Zoran

    2007-01-01

    Full Text Available During the period from February until March 2004, 108 samples of soft cheese originating from markets of Pancevo, Subotica and Belgrade were examined. Microbiological analyses of the cheese samples to the presence of Escherichia coli was performed using methods described in the Regulations on methods for performing microbiological analyses and super analyses of consumer articles, while the presence of bacteria Enteroccocus spp. was performed on the dexter agar. From 108 samples of soft cheese from the territories of Pancevo, Belgrade and Subotica were isolated: Enterococcus spp. from 96% and Escherichia coli from 69%, cheese samples. Verocytotoxic E.coli was not isolated from any of the taken cheese samples.

  7. Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam

    NARCIS (Netherlands)

    Trung, Nguyen Vinh; Nhung, Hoang Ngoc; Carrique-Mas, Juan J; Mai, Ho Huynh; Tuyen, Ha Thanh; Campbell, James; Nhung, Nguyen Thi; Van Minh, Pham; Wagenaar, Jaap A|info:eu-repo/dai/nl/126613354; Mai, Nguyen Thi Nhu; Hieu, Thai Quoc; Schultsz, Constance; Hoa, Ngo Thi

    2016-01-01

    BACKGROUND: Enteroaggregative (EAEC) and Shiga-toxin producing Escherichia coli (STEC) are a major cause of diarrhea worldwide. E. coli carrying both virulence factors characteristic for EAEC and STEC and producing extended-spectrum beta-lactamase caused severe and protracted disease during an

  8. Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam

    NARCIS (Netherlands)

    Trung, Nguyen Vinh; Nhung, Hoang Ngoc; Carrique-Mas, Juan J.; Mai, Ho Huynh; Tuyen, Ha Thanh; Campbell, James; Nhung, Nguyen Thi; Minh, Van Pham; Wagenaar, Jaap A.; Mai, Nguyen Thi Nhu; Hieu, Thai Quoc; Schultsz, Constance; Hoa, Ngo Thi

    2016-01-01

    Background: Enteroaggregative (EAEC) and Shiga-toxin producing Escherichia coli (STEC) are a major cause of diarrhea worldwide. E. coli carrying both virulence factors characteristic for EAEC and STEC and producing extended-spectrum beta-lactamase caused severe and protracted disease during an

  9. Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam

    NARCIS (Netherlands)

    Trung, Nguyen Vinh; Nhung, Hoang Ngoc; Carrique-Mas, Juan J.; Mai, Ho Huynh; Tuyen, Ha Thanh; Campbell, James; Nhung, Nguyen Thi; Minh, Van Pham; Wagenaar, Jaap A.; Mai, Nguyen Thi Nhu; Hieu, Thai Quoc; Schultsz, Constance; Hoa, Ngo Thi

    2016-01-01

    Background: Enteroaggregative (EAEC) and Shiga-toxin producing Escherichia coli (STEC) are a major cause of diarrhea worldwide. E. coli carrying both virulence factors characteristic for EAEC and STEC and producing extended-spectrum beta-lactamase caused severe and protracted disease during an ou

  10. First detection of CTX-M-1, CMY-2, and QnrB19 resistance mechanisms in fecal Escherichia coli isolates from healthy pets in Tunisia.

    Science.gov (United States)

    Sallem, Rym Ben; Gharsa, Haythem; Slama, Karim Ben; Rojo-Bezares, Beatriz; Estepa, Vanesa; Porres-Osante, Nerea; Jouini, Ahlem; Klibi, Naouel; Sáenz, Yolanda; Boudabous, Abdellatif; Torres, Carmen

    2013-02-01

    Our objective was to analyze the carriage rate of extended-spectrum β-lactamase (ESBL)- and plasmidic AmpC β-lactamase (pAmpC)-producing Escherichia coli isolates in fecal samples of healthy pets (dogs and cats) and to characterize the recovered isolates for the presence of other resistance genes and integrons. Eighty fecal samples of healthy pets were inoculated in MacConkey agar plates supplemented with cefotaxime (2 μg/mL) for cefotaxime-resistant (CTX(R)) E. coli recovery. CTX(R) E. coli isolates were detected in 14 of the 80 fecal samples (17.5%) and the following β-lactamase genes (number of isolates) were detected: bla(CTX-M-1) (8), bla(CTX-M-1)+bla(TEM-1b) (3)(,) bla(CTX-M-1)+bla(TEM-1c) (1), bla(CTX-M-1)+bla(TEM-135) (1), and bla(CMY-2)+bla(TEM-1b) (1). The 14 E. coli were distributed into the phylogroups B1 (6 isolates), A (5), and D (3). The qnrB19 gene was detected in one CTX-M-1-producing strain of phylogroup D. Five isolates contained class 1 integrons with the following arrangements: dfrA17-aadA5 (2 isolates), dfrA1-aadA1 (1), and dfrA17-aadA5/ dfrA1-aadA1 (2 isolates). The virulence genes fimA and/or aer were detected in all CTX(R) strains. In this study, the pet population harbored β-lactamase and quinolone resistance genes of special interest in human health that potentially could be transmitted to humans in close contact with them.

  11. Free RNA polymerase in Escherichia coli.

    Science.gov (United States)

    Patrick, Michael; Dennis, Patrick P; Ehrenberg, Mans; Bremer, Hans

    2015-12-01

    The frequencies of transcription initiation of regulated and constitutive genes depend on the concentration of free RNA polymerase holoenzyme [Rf] near their promoters. Although RNA polymerase is largely confined to the nucleoid, it is difficult to determine absolute concentrations of [Rf] at particular locations within the nucleoid structure. However, relative concentrations of free RNA polymerase at different growth rates, [Rf]rel, can be estimated from the activities of constitutive promoters. Previous studies indicated that the rrnB P2 promoter is constitutive and that [Rf]rel in the vicinity of rrnB P2 increases with increasing growth rate. Recently it has become possible to directly visualize Rf in growing Escherichia coli cells. Here we examine some of the important issues relating to gene expression based on these new observations. We conclude that: (i) At a growth rate of 2 doublings/h, there are about 1000 free and 2350 non-specifically DNA-bound RNA polymerase molecules per average cell (12 and 28%, respectively, of 8400 total) which are in rapid equilibrium. (ii) The reversibility of the non-specific binding generates more than 1000 free RNA polymerase molecules every second in the immediate vicinity of the DNA. Of these, most rebind non-specifically to the DNA within a few ms; the frequency of non-specific binding is at least two orders of magnitude greater than specific binding and transcript initiation. (iii) At a given amount of RNA polymerase per cell, [Rf] and the density of non-specifically DNA-bound RNA polymerase molecules along the DNA both vary reciprocally with the amount of DNA in the cell. (iv) At 2 doublings/h an E. coli cell contains, on the average, about 1 non-specifically bound RNA polymerase per 9 kbp of DNA and 1 free RNA polymerase per 20 kbp of DNA. However some DNA regions (i.e. near active rRNA operons) may have significantly higher than average [Rf].

  12. Quinolone Resistance among Salmonella enterica from Cattle, Broilers and Swine in Denmark

    DEFF Research Database (Denmark)

    Wiuff, C.; Baggesen, Dorte Lau; Madsen, M.

    2000-01-01

    This study was conducted to determine the susceptibility to nalidixic acid and fluoroquinolones of Salmonella Dublin, S. Enteritidis, and S. Typhimurium isolates from cattle, broilers, and pigs over time in Denmark and to characterise the gyrA, gyrB, and parC genes in quinolone-resistant isolates...

  13. The evidence for clonal spreading of quinolone resistance with a particular clonal complex of Campylobacter jejuni.

    Science.gov (United States)

    Kovač, J; Cadež, N; Lušicky, M; Nielsen, E Møller; Ocepek, M; Raspor, P; Možina, S Smole

    2014-12-01

    Campylobacter is the most prevalent cause of bacterial gastroenteritis worldwide and it represents a significant public health risk of increasing severity due to its escalating resistance to clinically important quinolone and macrolide antibiotics. As a zoonotic pathogen Campylobacter is transmitted along the food chain and naturally cycles from environmental waters, feedstuff, animals and food to humans. We determined antibiotic resistance profiles, as well as multilocus sequence types and flaA-SVR types for 52 C. jejuni isolated in Slovenia from human, animal, raw and cured chicken meat and water samples. Twenty-eight different sequence types, arranged in ten clonal complexes, three new allele types and five new sequence types were identified, indicating the relatively high diversity in a small group of strains. The assignment of strains from different sources to the same clonal complexes indicates their transmission along the food supply chain. The most prevalent clonal complex was CC21, which was also the genetic group with 95% of quinolone-resistant strains. Based on the genetic relatedness of these quinolone-resistant strains identified by polymerase chain reaction with a mismatch amplification mutation assay and sequencing of the quinolone resistance-determining region of the gyrA gene, we conclude that the high resistance prevalence observed indicates the local clonal spread of quinolone resistance with CC21.

  14. Contribution of topoisomerase IV mutation to quinolone resistance in Mycoplasma genitalium.

    Science.gov (United States)

    Yamaguchi, Yuko; Takei, Masaya; Kishii, Ryuta; Yasuda, Mitsuru; Deguchi, Takashi

    2013-04-01

    The mechanism of quinolone resistance in Mycoplasma genitalium remains poorly understood due to difficulties with in vitro culture, especially of clinical isolates. In this study, to confirm the association between mutations in topoisomerases and antimicrobial susceptibilities to quinolones, ciprofloxacin-resistant mutant strains were selected using the cultivable type strain ATCC 33530. Sequence analysis revealed that the mutant strains harbored mutations in topoisomerase IV: Gly81Cys in ParC, Pro261Thr in ParC, or Asn466Lys in ParE. The MICs of all quinolones tested against the mutant strains were 2- to 16-fold higher than those against the wild-type strain. No cross-resistance was observed with macrolides or tetracyclines. We determined the inhibitory activities of quinolones against DNA gyrase and topoisomerase IV in order to investigate the correlation between antimicrobial susceptibility and inhibitory activity against the target enzymes, considered the primary targets of quinolones. Furthermore, using enzymatic analysis, we confirmed that Gly81Cys in the ParC quinolone resistance-determining region (QRDR) contributed to quinolone resistance. This is the first study to isolate quinolone-resistant mutant strains of M. genitalium harboring substitutions in the parC or parE gene in vitro and to measure the inhibitory activities against the purified topoisomerases of M. genitalium.

  15. Plasmid-mediated quinolone resistance among non-typhi Salmonella enterica isolates, USA

    Science.gov (United States)

    We determined the prevalence of plasmid-mediated quinolone resistance mechanisms among non-Typhi Salmonella (NTS) spp. isolates from humans, food animals, and retail meat in the United States in 2007. Fifty-one (2.4%) of human isolates (n=2165), 5 (1.6%) of isolates from animal isolates (n=1915) an...

  16. The versatile strategies of Escherichia coli pathotypes: a mini review

    Directory of Open Access Journals (Sweden)

    C. P. Sousa

    2006-01-01

    Full Text Available The widespread species Escherichia coli includes a broad variety of different types, ranging from highly pathogenic strains to avirulent isolates. Few microorganisms are as versatile as E. coli. Pathogenic strains remain a leading cause of severe and persistent infant diarrhea in developing countries. They may be limited to colonization of a mucosal surface or can disseminate throughout the body and have been implicated in urinary tract infection, sepsis/meningitis and gastrointestinal infection. The human gastrointestinal tract is susceptible to diarrheagenic E. coli infections. Escherichia coli have effectively managed to subvert the host cytoskeleton for their own purposes causing substantial diarrheal disease, a major public health problem worldwide. This review deals with the different strategies regarding E. coli as a pathogen and the virulence traits of its pathotypes highlighting the species as a commensal, opportunistic and specialized pathogen.

  17. Environmental Escherichia coli: Ecology and public health implications - A review

    Science.gov (United States)

    Jang, Jeonghwan; Hur, Hor-Gil; Sadowsky, Michael J.; Byappanahalli, Muruleedhara; Yan, Tao; Ishii, Satoshi

    2017-01-01

    Escherichia coli is classified as a rod-shaped, Gram-negative bacterium in the family Enterobacteriaceae. The bacterium mainly inhabits the lower intestinal tract of warm-blooded animals, including humans, and is often discharged into the environment through feces or wastewater effluent. The presence of E. coli in environmental waters has long been considered as an indicator of recent fecal pollution. However, numerous recent studies have reported that some specific strains of E. coli can survive for long periods of time, and potentially reproduce, in extra-intestinal environments. This indicates that E. coli can be integrated into indigenous microbial communities in the environment. This naturalization phenomenon calls into question the reliability of E. coli as a fecal indicator bacterium (FIB). Recently, many studies reported that E. coli populations in the environment are affected by ambient environmental conditions affecting their long-term survival. Large-scale studies of population genetics provide the diversity and complexity of E. coli strains in various environments, affected by multiple environmental factors. This review examines the current knowledge on the ecology of E. coli strains in various environments in regards to its role as a FIB and as a naturalized member of indigenous microbial communities. Special emphasis is given on the growth of pathogenic E. coli in the environment, and the population genetics of environmental members of the genus Escherichia. The impact of environmental E. coli on water quality and public health is also discussed.

  18. Rapid Sterilization of Escherichia coli by Solution Plasma Process

    Science.gov (United States)

    Andreeva, Nina; Ishizaki, Takahiro; Baroch, Pavel; Saito, Nagahiro

    2012-12-01

    Solution plasma (SP), which is a discharge in the liquid phase, has the potential for rapid sterilization of water without chemical agents. The discharge showed a strong sterilization performance against Escherichia coli bacteria. The decimal value (D value) of the reduction time for E. coli by this system with an electrode distance of 1.0 mm was estimated to be approximately 1.0 min. Our discharge system in the liquid phase caused no physical damage to the E. coli and only a small increase in the temperature of the aqueous solution. The UV light generated by the discharge was an important factor in the sterilization of E. coli.

  19. Detection of Escherichia coli in wastewater based on enzyme immunoassay

    Institute of Scientific and Technical Information of China (English)

    XI Haiyan; CAI Qiang; HE Miao; SHI Hanchang

    2007-01-01

    This research describes a fast detection method on the basis of enzyme-linked immunosorbent assay (ELISA)for Escherichia coli in drainage of wastewater treatment plants.Optimized conditions such as the reaction format(sandwich or direct),the concentrations of diluted horseradish peroxidase (HRP)-E.coli conjugate,and anti-HPR antibody and pretreatment of E.coli were studied.Those results showed that the linear range of detection for E.coli was 10 cfu/mL-6×104 cfu/mL.Compared with conventional methods,it is a convenient and sensitive detection method with low cost.

  20. Fluorogenic assay for rapid detection of Escherichia coli in food.

    OpenAIRE

    1985-01-01

    An assay procedure to screen for Escherichia coli in foods by using 4-methylumbelliferyl-beta-D-glucuronide (MUG) incorporated into lauryl tryptose (LST) broth was evaluated. The beta-glucuronidase produced by E. coli cleaves the MUG substrate to yield a fluorescent end product. E. coli-negative samples can be identified by lack of fluorescence in LST-MUG within 24 h. MUG was not inhibitory to coliforms and E. coli. Over 1,400 food and dairy samples were tested to compare the standard three-t...

  1. Chromosomal features of Escherichia coli serotype O2:K2, an avian pathogenic E. coli

    DEFF Research Database (Denmark)

    Jørgensen, Steffen L; Kudirkiene, Egle; Li, Lili

    2017-01-01

    Escherichia coli causing infection outside the gastrointestinal system are referred to as extra-intestinal pathogenic E. coli. Avian pathogenic E. coli is a subgroup of extra-intestinal pathogenic E. coli and infections due to avian pathogenic E. coli have major impact on poultry production economy...... and welfare worldwide. An almost defining characteristic of avian pathogenic E. coli is the carriage of plasmids, which may encode virulence factors and antibiotic resistance determinates. For the same reason, plasmids of avian pathogenic E. coli have been intensively studied. However, genes encoded...... by the chromosome may also be important for disease manifestation and antimicrobial resistance. For the E. coli strain APEC_O2 the plasmids have been sequenced and analyzed in several studies, and E. coli APEC_O2 may therefore serve as a reference strain in future studies. Here we describe the chromosomal features...

  2. Unexpected distribution of the fluoroquinolone-resistance gene qnrB in Escherichia coli isolates from different human and poultry origins in Ecuador.

    Science.gov (United States)

    Armas-Freire, Paulina I; Trueba, Gabriel; Proaño-Bolaños, Carolina; Levy, Karen; Zhang, Lixin; Marrs, Carl F; Cevallos, William; Eisenberg, Joseph N S

    2015-06-01

    Fluoroquinolone resistance can be conferred through chromosomal mutations or by the acquisition of plasmids carrying genes such as the quinolone resistance gene (qnr). In this study, 3,309 strains of commensal Escherichia coli were isolated in Ecuador from: (i) humans and chickens in a rural northern coastal area (n = 2368, 71.5%) and (ii) chickens from an industrial poultry operation (n = 827, 25%). In addition, 114 fluoroquinolone-resistant strains from patients with urinary tract infections who were treated at three urban hospitals in Quito, Ecuador were analyzed. All of the isolates were subjected to antibiotic susceptibility screening. Fluoroquinolone-resistant isolates (FRIs) were then screened for the presence of qnrB genes. A significantly higher phenotypic resistance to fluoroquinolones was determined in E. coli strains from chickens in both the rural area (22%) and the industrial operation (10%) than in strains isolated from humans in the rural communities (3%). However, the rates of qnrB genes in E. coli isolates from healthy humans in the rural communities (11 of 35 isolates, 31%) was higher than in chickens from either the industrial operations (3 of 81 isolates, 6%) or the rural communities (7 of 251 isolates, 2.8%). The occurrence of qnrB genes in human FRIs obtained from urban hospitals was low (1 of 114 isolates, 0.9%). These results suggested that the qnrB gene is more widely distributed in rural settings, where antibiotic usage is low, than in urban hospitals and industrial poultry operations. The role of qnrB in clinical resistance to fluoroquinolones is thus far unknown.

  3. The asymptomatic bacteriuria Escherichia coli strain 83972 outcompetes uropathogenic E. coli strains in human urine

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Ulett, G.C.; Schembri, M.A.

    2006-01-01

    Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic urinary tract infections (UTI), very little is known about the mechanisms by which these strains colonize the human urinary tract...

  4. Recurrent Hemolytic and Uremic Syndrome Induced by Escherichia Coli

    Science.gov (United States)

    Commereuc, Morgane; Weill, Francois-Xavier; Loukiadis, Estelle; Gouali, Malika; Gleizal, Audrey; Kormann, Raphaël; Ridel, Christophe; Frémeaux-Bacchi, Véronique; Rondeau, Eric; Hertig, Alexandre

    2016-01-01

    Abstract A widespread belief is that typical hemolytic and uremic syndrome (HUS) does not recur. We report the case of a patient infected twice with raw milk taken from his own cow and containing a Shiga toxin–producing Escherichia coli O174:H21 that induced recurrent HUS causing severe renal and cerebral disorders. A genomic comparison of the human and bovine Shiga toxin–producing Escherichia coli O174:H21 isolates revealed that they were identical. Typical HUS may recur. Since milk from this animal was occasionally distributed locally, thereby posing a serious threat for the whole village, this particular cow was destroyed. PMID:26735524

  5. Obscured phylogeny and possible recombinational dormancy in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Sawyer Stanley A

    2011-06-01

    Full Text Available Abstract Background Escherichia coli is one of the best studied organisms in all of biology, but its phylogenetic structure has been difficult to resolve with current data and analytical techniques. We analyzed single nucleotide polymorphisms in chromosomes of representative strains to reconstruct the topology of its emergence. Results The phylogeny of E. coli varies according to the segment of chromosome analyzed. Recombination between extant E. coli groups is largely limited to only three intergroup pairings. Conclusions Segment-dependent phylogenies most likely are legacies of a complex recombination history. However, E. coli are now in an epoch in which they no longer broadly share DNA. Using the definition of species as organisms that freely exchange genetic material, this recombinational dormancy could reflect either the end of E. coli as a species, or herald the coalescence of E. coli groups into new species.

  6. Arginine Catabolism and the Arginine Succinyltransferase Pathway in Escherichia coli

    OpenAIRE

    Schneider, Barbara L.; Kiupakis, Alexandros K.; Reitzer, Lawrence J.

    1998-01-01

    Arginine catabolism produces ammonia without transferring nitrogen to another compound, yet the only known pathway of arginine catabolism in Escherichia coli (through arginine decarboxylase) does not produce ammonia. Our aims were to find the ammonia-producing pathway of arginine catabolism in E. coli and to examine its function. We showed that the only previously described pathway of arginine catabolism, which does not produce ammonia, accounted for only 3% of the arginine consumed. A search...

  7. Probability of recovering pathogenic Escherichia coli from foods.

    OpenAIRE

    Hill, W E; Ferreira, J. L; Payne, W L; Jones, V.M.

    1985-01-01

    The probability of recovering pathogenic Escherichia coli from food by the Bacteriological Analytical Manual method was determined by the effects of several factors: the number of strains per food, the ability of pathogenic strains to survive enrichment, and the frequency of plasmid loss during enrichment. Biochemical patterns indicated the presence of about six E. coli strains per food sample. About half of the strains isolated from humans did not survive enrichment. Among those which grew, ...

  8. Engineered biosynthesis of bacterial aromatic polyketides in Escherichia coli

    OpenAIRE

    Zhang, Wenjun; Li, Yanran; Tang, Yi

    2008-01-01

    Bacterial aromatic polyketides are important therapeutic compounds including front line antibiotics and anticancer drugs. It is one of the last remaining major classes of natural products of which the biosynthesis has not been reconstituted in the genetically superior host Escherichia coli. Here, we demonstrate the engineered biosynthesis of bacterial aromatic polyketides in E. coli by using a dissected and reassembled fungal polyketide synthase (PKS). The minimal PKS of the megasynthase PKS4...

  9. Osmoprotection of Escherichia coli by ectoine: uptake and accumulation characteristics.

    OpenAIRE

    Jebbar, M; Talibart, R; Gloux, K; Bernard, T.; BLANCO, C.

    1992-01-01

    Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) is a cyclic amino acid, identified as a compatible solute in moderately halophilic bacteria. Exogenously provided ectoine was found to stimulate growth of Escherichia coli in media of inhibitory osmotic strength. The stimulation was independent of any specific solute, electrolyte or nonelectrolyte. It is accumulated in E. coli cells proportionally to the osmotic strength of the medium, and it is not metabolized. Its osmoprotect...

  10. Detection of virulence factors of Uropathoigenic Escherichia coli isolates from infertile women high vaginal swabs

    Directory of Open Access Journals (Sweden)

    Farhad Safarpourdehkourdi

    2014-03-01

    Conclusion: The high vaginal Escherichia coli harbored certain virulence genes of uropathogenic Escherichia coli strains. The urinary tract infections should be treated well to diminish its upstream transfer into vagina. Some more investigation should be perform for identifying the epidemiological aspects of uropathogenic Escherichia coli in high vaginal part of infertile women.

  11. 76 FR 72331 - Shiga Toxin-Producing Escherichia coli in Certain Raw Beef Products

    Science.gov (United States)

    2011-11-23

    ... Toxin-Producing Escherichia coli in Certain Raw Beef Products AGENCY: Food Safety and Inspection Service... methods for controlling non-O157 Shiga toxin-producing Escherichia coli in raw, intact and non-intact beef... Escherichia coli in raw, intact and non-intact beef products and product components on or before December...

  12. [The clinical characteristics analysis of Escherichia coli bloodstream infection].

    Science.gov (United States)

    Zhang, M; Huang, J A; Chen, Y B

    2016-05-17

    To explore the clinical features of Escherichia coli bloodstream infection. The clinical data of underlying diseases, antimicrobial susceptibility, temperature at blood sampling, results of routine blood tests, venous catheterization, therapy and prognosis of Escherichia coli bloodstream infection in the First Affiliated Hospital of Soochow University from January 2007 to December 2014 were analyzed retrospectively. The pathogens were routinely isolated and identified. Susceptibilities against antimicrobial agents were determined by Kirby-Bauer methods. All patients had at least one underlying disease. Most of the basic diseases were hematological malignancies, malignant solid tumors, pneumonia and so on. Body temperature was normal in 40 patients (6.4%), fever in 587 patients (93.5%) and low temperature in 1 patient. There were 252 patients with leukopenia (40.1%), 237 patients with granulocytopenia (37.7%) and 216 patients with agranulocytosis. The resistance rate to imipenem was 3.3%, which was the lowest among the total antimicrobial susceptibilities of 628 Escherichia Coli. The extended-spectrum-β-lactamase (ESBL)-producing strains accounted for 53.8% among the total patients. The resistance rates of ESBLs-producing-Escherichia coli for the Sulfamethoxazole, Ampicillin, Gentamicin, Cefazolin, Cefuroxime, Cefotaxime, Ceftriaxone, Cefepime, Ceftazidime, Cefoperazone, Piperacillin and Ciprofloxacin were 80.2%, 100.0%, 62.4%, 99.1%, 99.1%, 98.8%, 98.2%, 48.5%, 50.6%, 95.0%, 98.2%, 79.6%, respectively, which were higher than that of non-ESBLs-producing-Escherichia coli (67.9%, 79.7%, 47.6%, 50.0%, 47.2%, 41.0%, 40.3%, 27.2%, 24.1%, 40.0%, 56.2%, 58.3%, respectively), the differences were significant statistically (χ(2)=12.33, 75.90, 13.92, 209.00, 224.94, 259.25, 256.59, 27.79, 46.19, 222.85, 165.08, 33.59, all PEscherichia coli bloodstream infection. The antimicrobial resistance rate of ESBLs-producing-Escherichia coli is higher than that of none-ESBLs-producing-Escherichia

  13. Cervical celullitis in broiler chickens for Escherichia coli/ Celulite cervical em frangos de corte causada por Escherichia coli

    Directory of Open Access Journals (Sweden)

    Ivens Gomes Guimarães

    2002-05-01

    Full Text Available In this paper was report the isolation of Escherichia coli in broiler chickens with cellulitis in the cervical region. It was carried through the isolation of E. coli of the lesion of cellulitis from broilers and carried through histopathological examination of skin that had characterized the lesion. Focal ulcerations of epidermis, fibrin in dermis and difuse infiltrated by lymphocytes and heterophils on subcutaneous tissues.Neste trabalho, relata-se o isolamento de Escherichia coli em frangos de corte apresentando lesão de celulite na região cervical. Foi realizado o isolamento de E. coli da lesão de celulite e realizado exames histopatológicos que caracterizaram a lesão. Na epiderme foram verificadas lesões ulcerativas, presença de fibrina na derme e infiltração difusa de linfócitos e heterófilos no tecido subcutâneo.

  14. Ciprofloxacin Treatment Failure in a Murine Model of Pyelonephritis Due to an AAC(6′)-Ib-cr-Producing Escherichia coli Strain Susceptible to Ciprofloxacin In Vitro

    Science.gov (United States)

    Guillard, T.; Cambau, E.; Chau, F.; Massias, L.; de Champs, C.

    2013-01-01

    AAC(6′)-Ib-cr is a plasmid-mediated quinolone resistance mechanism described worldwide for Escherichia coli. Since it confers in vitro only a low level of resistance to ciprofloxacin, we evaluated its impact on the in vivo activity of ciprofloxacin. Isogenic strains were obtained by transferring plasmid p449, harboring aac(6′)-Ib-cr, into the quinolone-susceptible strain E. coli CFT073-RR and its D87G gyrA mutant. MICs were 0.015, 0.06, 0.25, and 0.5 μg/ml against E. coli strains CFT073-RR, CFT073-RR/p449, CFT073-RR GyrAr, and CFT073-RR GyrAr/p449, respectively. Bactericidal activity was reduced at 1× the MIC for the three resistant derivatives, while at a fixed concentration of 0.5 μg/ml, 99.9% killing was observed for all strains except E. coli CFT073-RR GyrAr/p449. In the murine model of pyelonephritis, an optimal regimen of ciprofloxacin (10 mg/kg of body weight twice a day [b.i.d.]) significantly decreased the bacterial count in the kidneys of mice infected with E. coli CFT073 (1.6 versus 4.3 log10 CFU/g of kidney compared to untreated controls; P = 0.0001), while no significant decrease was observed for E. coli CFT073-RR/p449 (2.7 versus 3.1 log10 CFU/g; P = 0.84), E. coli CFT073-RR GyrAr (4.2 versus 4.1 log10 CFU/g; P = 0.35), or E. coli CFT073-RR GyrAr/p449 (2.9 versus 3.6 log10 CFU/g; P = 0.47). While pharmacokinetic and pharmacodynamic (PK/PD) parameters accounted for ciprofloxacin failure against gyrA-containing mutants, this was not the case for the aac(6′)-Ib-cr-containing strains, suggesting an in situ hydrolysis of ciprofloxacin in the latter case. PMID:24018262

  15. YeeO from Escherichia coli exports flavins.

    Science.gov (United States)

    McAnulty, Michael J; Wood, Thomas K

    2014-01-01

    Multidrug and toxic compound extrusion (MATE) proteins help maintain cellular homeostasis by secreting metabolic wastes. Flavins may occur as cellular waste products, with their production and secretion providing potential benefit for industrial applications related to biofuel cells. Here we find that MATE protein YeeO from Escherichia coli exports both flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). Significant amounts of flavins were trapped intracellularly when YeeO was produced indicating transport limits secretion of flavins. Wild-type E. coli secreted 3 flavins (riboflavin, FMN, and FAD), so E. coli likely produces additional flavin transporters.

  16. Escherichia coli O26 IN RAW BUFFALO MILK: PRELIMINARY RESULTS

    Directory of Open Access Journals (Sweden)

    A. Rella

    2013-02-01

    Full Text Available Escherichia coli O26 is considered to be one of the most important food-borne pathogen. In this study, 120 buffalo milk samples collected in Lazio and in Apulia regions were tested for the presence of E. coli O26. One buffalo milk sample (0,8% tested positive for E. coli O26; the isolate was positive at the verocytotoxicity test and it showed resistance properties to different antimicrobial classes. These preliminary results highlight the need to monitor the foods of animal origin used for production and eaten by a wide range of persons, respect VTEC organism.

  17. Antibiotic-resistant Escherichia coli bacteria, including strains with genes encoding the extended-spectrum beta-lactamase and QnrS, in waterbirds on the Baltic Sea Coast of Poland.

    Science.gov (United States)

    Literak, Ivan; Dolejska, Monika; Janoszowska, Dagmar; Hrusakova, Jolana; Meissner, Wlodzimierz; Rzyska, Hanna; Bzoma, Szymon; Cizek, Alois

    2010-12-01

    Individual cloacal swabs of mallards (Anas platyrhynchos) and of herring gulls (Larus argentatus), as well as samples of waterbird feces obtained in 2008 and 2009, were cultivated for Escherichia coli. Isolates of E. coli were tested for susceptibilities to 12 antimicrobial agents by the disk diffusion method. Moreover, the samples were subcultivated on MacConkey agar (MCA) containing cefotaxime (2 mg liter(-1)) to detect E. coli with extended-spectrum beta-lactamase (ESBL) and subsequently on MCA supplemented with ciprofloxacin (0.05 mg liter(-1)) and MCA with nalidixic acid (20 mg liter(-1)) to isolate fluoroquinolone-resistant E. coli. PCR was used to detect specific antibiotic resistance genes. We found 9 E. coli isolates producing ESBL with bla genes: bla(CTX-M-1) (6 isolates), bla(CTX-M-9) plus bla(TEM-1b) (1 isolate), bla(CTX-M-15) plus bla(OXA-1) (1 isolate), and bla(SHV-12) (1 isolate). In the isolate with bla(CTX-M-15), the gene aac(6)-Ib-cr was also detected. The bla genes were harbored by transferable plasmids of the IncN and IncI1 groups. Nine quinolone-resistant E. coli isolates with qnrS genes were found and characterized. The gene qnrS was associated with a Tn3-like transposon on the IncX1 plasmid together with bla(TEM-1) in two isolates. The gene qnrS was also harbored by conjugative plasmids of the IncN and IncX2 groups. Even if populations of wild birds are not directly influenced by antibiotic practice, we have demonstrated that antibiotic-resistant E. coli strains, including strains with various ESBL and qnrS genes, are found in the feces of wild birds on the coast of the Baltic Sea in Poland.

  18. antimicrobial susceptibility and plasmids from escherichia coli ...

    African Journals Online (AJOL)

    2001-10-10

    Oct 10, 2001 ... transmission to humans of E. coli containing antibiotic resistance plasmids ... resistant micro-organisms, which may in turn transfer resistance to .... cells were washed with sterile normal saline to remove leached. Я-lactamase ...

  19. ANTIMICIROBIAL SUSCEPTIBILITY PATTERNS OF Escherichia coli ...

    African Journals Online (AJOL)

    DR. AMINU

    aetiological agents of diarrhoea diseases of humans in developing ... Pathogenic organisms have developed a number of elaborate .... reported that E.coli isolated from animals haboured plasmids .... coil 0157:H7 as a model of entry of a new.

  20. Synergistic effects in mixed Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Reisner, A.; Holler, B.M.; Molin, Søren

    2006-01-01

    the strongest effects was most often linked to conjugative transmission of natural plasmids carried by the E. coli isolates (70%). Thus, the capacity of an isolate to promote the biofilm through cocultivation was (i) transferable to the K-12 strain, (ii) was linked with the acquisition of conjugation genes...... promotion in this system is not dependent on the laboratory strain and that the described model system could provide relevant insights on mechanisms of biofilm development in natural E. coli populations....

  1. Antibiotic treatment of verocytotoxin-producing Escherichia coli (VTEC) infection

    DEFF Research Database (Denmark)

    Agger, Morten; Scheutz, Flemming; Villumsen, Steen;

    2015-01-01

    OBJECTIVES: A consensus has existed on not to treat verocytotoxin-producing Escherichia coli (VTEC)-infected individuals with antibiotics because of possible subsequent increased risk of developing haemolytic uraemic syndrome (HUS). The aim of this systematic review is to clarify the risk...

  2. Escherichia coli mutants with a temperature-sensitive alcohol dehydrogenase.

    OpenAIRE

    Lorowitz, W; Clark, D.

    1982-01-01

    Mutants of Escherichia coli resistant to allyl alcohol were selected. Such mutants were found to lack alcohol dehydrogenase. In addition, mutants with temperature-sensitive alcohol dehydrogenase activity were obtained. These mutations, designated adhE, are all located at the previously described adh regulatory locus. Most adhE mutants were also defective in acetaldehyde dehydrogenase activity.

  3. New types of Escherichia coli recombination-deficient mutants.

    Science.gov (United States)

    Freifelder, D

    1976-11-01

    A set of Escherichia coli mutants deficient in intramolecular recombination and different from those previously found is described. All have temperature-sensitive lethal mutations. The mutants have been characterized with respect to the following properties: the Pap phenotype, deoxyribonucleic acid synthesis, sensitivity to ultraviolet light, ability to support the growth of phage lambda, filament formation, and mutation frequency.

  4. Escherichia coli and virus isolated from ''sticky kits''

    DEFF Research Database (Denmark)

    Jørgensen, M.; Scheutz, F.; Strandbygaard, Bertel

    1996-01-01

    A total of 121 Escherichia coli strains isolated from 3-week-old mink kits were serotyped and examined for virulence factors. 56 strains were isolated from healthy kits while 65 were from ''sticky kits''. Among these, 34 different serotypes were detected. No difference in serotypes or the presenc...

  5. armA and aminoglycoside resistance in Escherichia coli.

    Science.gov (United States)

    González-Zorn, Bruno; Teshager, Tirushet; Casas, María; Porrero, María C; Moreno, Miguel A; Courvalin, Patrice; Domínguez, Lucas

    2005-06-01

    We report armA in an Escherichia coli pig isolate from Spain. The resistance gene was borne by self-transferable IncN plasmid pMUR050. Molecular analysis of the plasmid and of the armA locus confirmed the spread of this resistance determinant.

  6. armA and Aminoglycoside Resistance in Escherichia coli

    OpenAIRE

    González-Zorn, Bruno; Teshager, Tirushet; Casas, María; Porrero, María C.; Moreno, Miguel A.; Courvalin, Patrice; Domínguez, Lucas

    2005-01-01

    We report armA in an Escherichia coli pig isolate from Spain. The resistance gene was borne by self-transferable IncN plasmid pMUR050. Molecular analysis of the plasmid and of the armA locus confirmed the spread of this resistance determinant.

  7. Combating enteropathogenic Escherichia coli (EPEC) infections: the way forward

    OpenAIRE

    Michael S Donnenberg; Finlay, B. Brett

    2013-01-01

    Enteropathogenic Escherichia coli (EPEC) strains continue to cause severe and sometimes fatal infantile diarrhea, particularly in Africa. Increased efforts at diagnosis, defining the clinical spectrum of disease, understanding pathogenic mechanisms, and delineating immune responses are desperately needed to develop new strategies to combat EPEC.

  8. Characterization of Escherichia coli nucleoids released by osmotic shock.

    NARCIS (Netherlands)

    Wegner, A.S.; Alexeeva, S.; Odijk, T.; Woldringh, C.L.

    2012-01-01

    Nucleoids were isolated by osmotic shock from Escherichia coli spheroplasts at relatively low salt concentrations and in the absence of detergents. Sucrose-protected cells, made osmotically sensitive by growth in the presence of ampicillin or by digestion with low lysozyme concentrations (50-5 μg/ml

  9. Characterization of Escherichia coli nucleoids released by osmotic shock

    NARCIS (Netherlands)

    Wegner, S.; Alexeeva, S.V.; Odijk, T.; Woldringh, C.L.

    2012-01-01

    Nucleoids were isolated by osmotic shock from Escherichia coli spheroplasts at relatively low salt concentrations and in the absence of detergents. Sucrose-protected cells, made osmotically sensitive by growth in the presence of ampicillin or by digestion with low lysozyme concentrations (50–5 µg/ml

  10. Immunologic Control of Diarrheal Disease Due to Enterotoxigenic Escherichia coli

    Science.gov (United States)

    1984-01-01

    Classical Enteropathogenic (Serotyped) Escherichia coli Strains of Proven Pathogenicity. Infect. Immun. 38:798-801, 1982. 8. Levine, M.M. Vacunas Contra...Microbiol., 18:808-815, 1983. 8 15. Levine, M.M., Lanata, C. Progresos en Vacunas Contra Diarrea Bacteriana. Adelantos Microbiol. Enferm. Inf., 2:67-117

  11. Sequencing of Escherichia coli that cause persistent and transient Mastitis

    Science.gov (United States)

    The genomes of two strains of Escherichia coli that cause bovine mastitis were sequenced. These strains are known to be associated with persistent and transient mastitis: strain ECA-B causes a transient infection, and ECC-M leads to a persistent infection....

  12. Comparative Genomics of Escherichia coli Strains Causing Urinary Tract Infections

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk; Hancock, Viktoria; Schembri, Mark A.

    2011-01-01

    The virulence determinants of uropathogenic Escherichia coli have been studied extensively over the years, but relatively little is known about what differentiates isolates causing various types of urinary tract infections. In this study, we compared the genomic profiles of 45 strains from a range...

  13. Inactivation of Escherichia coli by titanium dioxide photocatalytic oxidation.

    Science.gov (United States)

    Titanium dioxide in the anatase crystalline form was used as a photocatalyst to generate hydroxyl radicals in a flowthrough water reactor. Experiments were performed on pure cultures of Escherichia coli in dechlorinated tap water and a surface water sample to evaluate the disinfe...

  14. Chromosomal replication incompatibility in Dam methyltransferase deficient Escherichia coli cells

    DEFF Research Database (Denmark)

    Freiesleben, Ulrik Von

    1996-01-01

    Dam methyltransferase deficient Escherichia coli cells containing minichromosomes were constructed. Free plasmid DNA could not be detected in these cells and the minichromosomes were found to be integrated in multiple copies in the origin of replication (oriC) region of the host chromosome...

  15. FimH-mediated autoaggregation of Escherichia coli

    DEFF Research Database (Denmark)

    Schembri, Mark; Christiansen, G.; Klemm, Per

    2001-01-01

    Autoaggregation is a phenomenon thought to contribute to colonization of mammalian hosts by pathogenic bacteria. Type 1 fimbriae are surface organelles of Escherichia coli that mediate D-mannose-sensitive binding to various host surfaces. This binding is conferred by the minor fimbrial component...

  16. DNA supercoiling depends on the phosphorylation potential in Escherichia coli

    DEFF Research Database (Denmark)

    Van Workum, M.; van Dooren, S.J.M; Oldenburg, N

    1996-01-01

    ATP/ADP ratios were varied in different ways and the degree of negative supercoiling was determined in Escherichia coli. Independent of whether the ATP/ADP ratio was reduced by a shift to anaerobic conditions, by addition of protonophore (dinitrophenol) or by potassium cyanide addition, DNA...

  17. Novel Aggregative Adherence Fimbria Variant of Enteroaggregative Escherichia coli

    DEFF Research Database (Denmark)

    Jønsson, Rie; Struve, Carsten; Boisen, Nadia

    2015-01-01

    Enteroaggregative Escherichia coli (EAEC) organisms belong to a diarrheagenic pathotype known to cause diarrhea and can be characterized by distinct aggregative adherence (AA) in a stacked-brick pattern to cultured epithelial cells. In this study, we investigated 118 EAEC strains isolated from...

  18. Peptide nucleic acid (PNA) antisense effects in Escherichia coli

    DEFF Research Database (Denmark)

    Good, L; Nielsen, P E

    1999-01-01

    Antisense peptide nucleic acid (PNA) can be used to control cell growth, gene expression and growth phenotypes in the bacteria Escherichia coli. PNAs targeted to the RNA components of the ribosome can inhibit translation and cell growth, and PNAs targeted to mRNA can limit gene expression with gene...

  19. Suppressors of DnaAATP imposed overinitiation in Escherichia coli

    DEFF Research Database (Denmark)

    Charbon, Godefroid; Riber, Leise; Cohen, Malene

    2011-01-01

    Chromosome replication in Escherichia coli is limited by the supply of DnaA associated with ATP. Cells deficient in RIDA (Regulatory Inactivation of DnaA) due to a deletion of the hda gene accumulate suppressor mutations (hsm) to counteract the overinitiation caused by an elevated DnaAATP level...

  20. Differential expression of the Escherichia coli autoaggregation factor antigen 43

    DEFF Research Database (Denmark)

    Schembri, Mark; Hjerrild, Louise; Gjermansen, Morten

    2003-01-01

    Antigen 43 (Ag43) is a self-recognizing surface adhesin found in most Escherichia coli strains. Due to its excellent cell-to-cell aggregation characteristics, Ag43 expression confers clumping and fluffing of cells and promotes biofilm formation. Ag43 expression is repressed by the cellular redox...

  1. Molecular characterization of the Escherichia coli asymptomatic bacteriuria strain 83972

    DEFF Research Database (Denmark)

    Klemm, Per; Hancock, Viktoria; Ulett, G.C.

    2006-01-01

    Escherichia coli 83972 is a clinical asymptomatia bacteriuric isolate that is able to colonize the human urinary bladder without inducing an immune response. Here we demonstrate that one of the mechanisms by which this strain has become attenuated is through the mutation of its genes encoding type...

  2. Binding of divalent magnesium by Escherichia coli phosphoribosyl diphosphate synthetase

    DEFF Research Database (Denmark)

    Willemoës, Martin; Hove-Jensen, Bjarne

    1997-01-01

    The mechanism of binding of the substrates Mg x ATP and ribose 5-phosphate as well as Mg2+ to the enzyme 5-phospho-D-ribosyl (alpha-1-diphosphate synthetase from Escherichia coli has been analyzed. By use of the competive inhibitors of ATP and ribose 5-phosphate binding, alpha,beta-methylene ATP ...

  3. A rapid differentiation method for enteroinvasive Escherichia coli.

    Science.gov (United States)

    Aribam, Swarmistha Devi; Hirota, Jiro; Kusumoto, Masahiro; Harada, Tomoyuki; Shiraiwa, Kazumasa; Ogawa, Yohsuke; Shimoji, Yoshihiro; Eguchi, Masahiro

    2014-03-01

    Enteroinvasive Escherichia coli (EIEC) comprise 21 major serotypes defined by the presence of O and H antigens, and diagnosis depends on determining its invasive potential. Using HEp-2 cells infected with an EIEC strain, we developed a simple growth-dependent assay that differentiated EIEC strain from non-invasive strains 6 h after infection.

  4. Kwantitatief gevoeligheidsonderzoek met intra- en extramurale isolaten van Escherichia coli

    NARCIS (Netherlands)

    de Neeling AJ; de Jong J; Overbeek BP; de Bruin RW; Dessens-Kroon M; van Klingeren B

    1990-01-01

    Three Dutch laboratories for medical microbiology collected a total number of 1432 strains of Escherichia coli. Of these 995 were obtained from routine samples taken in clinic and policlinic, 290 had been sent spontaneously by general practitioners for microbiological examination and 147 had been i

  5. Molecular characterization of the Escherichia coli asymptomatic bacteriuria strain 83972

    DEFF Research Database (Denmark)

    Klemm, Per; Hancock, Viktoria; Ulett, G.C.

    2006-01-01

    Escherichia coli 83972 is a clinical asymptomatia bacteriuric isolate that is able to colonize the human urinary bladder without inducing an immune response. Here we demonstrate that one of the mechanisms by which this strain has become attenuated is through the mutation of its genes encoding typ...

  6. Fragility of the permeability barrier of Escherichia coli

    NARCIS (Netherlands)

    Haest, C.W.M.; Gier, J. de; Es, G.A. van; Verkleij, A.J.; Deenen, L.L.M. van

    1972-01-01

    An unsaturated fatty acid requiring auxotroph of Escherichia coli was grown with addition of various unsaturated fatty acids. The permeability of the cells for erythritol appeared to be strongly dependent on the fatty acid incorporated in the membrane lipid. Below certain temperatures, depending on

  7. Stringent control of FLP recombinase in Escherichia coli.

    Science.gov (United States)

    Bowden, Steven D; Palani, Nagendra P; Libourel, Igor G L

    2017-02-01

    Site specific recombinases are invaluable tools in molecular biology, and are emerging as powerful recorders of cellular events in synthetic biology. We have developed a stringently controlled FLP recombinase system in Escherichia coli using an arabinose inducible promoter combined with a weak ribosome binding site.

  8. Escherichia coli and other Enterobacteriaceae: Food poisoning and health effects

    Science.gov (United States)

    The family Enterobactericeae consists of rod-shaped, Gram-negative, facultatively anaerobic, non-spore forming bacteria and also includes the food-borne pathogens, Cronobacter spp., Escherichia coli, Salmonella enterica, Shigella spp., and Yersinia spp. Illness caused by these pathogens is acquired...

  9. Escherichia coli as other Enterobacteriaceae: food poisoning and health effects

    Science.gov (United States)

    Many Escherichia coli strains are harmless, and they are an important commensal in the intestinal microflora; however, pathogenic strains also exist. The pathogenic strains can be divided into diarrhea-inducing strains and strains that reside in the intestines but only cause disease in bodily sites...

  10. Plasmid cloning vehicle for Haemophilus influenzae and Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, D.; Clayton, N.L.; Setlow, J.K.

    1982-09-01

    A new plasmid cloning vehicle (pDM2) was used to introduce a library of Haemophilus influenzae chromosomal fragments into H. influenzae. Transformants of the higly recombination-defective rec-1 mutant were more likely to contain exclusively recombinant plasmids after exposure to ligated DNA mixtures than was the wild type. pDM2 could replicate in Escherichia coli K-12.

  11. Norfloxacin resistance in a clinical isolate of Escherichia coli.

    Science.gov (United States)

    Aoyama, H; Sato, K; Kato, T; Hirai, K; Mitsuhashi, S

    1987-01-01

    Analysis of DNA gyrase supercoiling and of norfloxacin uptake in Escherichia coli GN14176, a moderately norfloxacin-resistant clinical isolate, indicated that resistance was associated with both an altered drug target and a reduction in drug uptake. Images PMID:2829712

  12. Kwantitatief gevoeligheidsonderzoek met intra- en extramurale isolaten van Escherichia coli

    NARCIS (Netherlands)

    de Neeling AJ; de Jong J; Overbeek BP; de Bruin RW; Dessens-Kroon M; van Klingeren B

    1990-01-01

    Three Dutch laboratories for medical microbiology collected a total number of 1432 strains of Escherichia coli. Of these 995 were obtained from routine samples taken in clinic and policlinic, 290 had been sent spontaneously by general practitioners for microbiological examination and 147 had been

  13. Prevalence of plasmid-mediated quinolone resistance determinants in Enterobacteriaceae strains isolated in North-East Italy.

    Science.gov (United States)

    Kocsis, B; Mazzariol, A; Kocsis, E; Koncan, R; Fontana, R; Cornaglia, G

    2013-02-01

    We investigated the prevalence of plasmid-mediated quinolone resistance genes in 756 clinical isolates of Enterobacteriaceae originating from Microbiology Diagnostic Laboratories of North-East Italy. Five point zero two percent of isolates carried a qnr determinant while the aac(6')-Ib-cr determinant was detected in 9·25% of isolates. We also investigated the association between the plasmid-mediated quinolone resistance and the beta-lactamase genes, and characterized the plasmids carrying these determinants of resistance.

  14. An outbreak of multidrug-resistant, quinolone-resistant Salmonella enterica serotype typhimurium DT104

    DEFF Research Database (Denmark)

    Molbak, K.; Baggesen, Dorte Lau; Aarestrup, Frank Møller

    1999-01-01

    , and tetracycline. An increasing proportion of DT104 isolates also have reduced susceptibility to fluoroquinolones. Methods The Danish salmonella surveillance program determines the phage types of all typhimurium strains from the food chain, and in the case of suspected outbreaks, five-drug-resistant strains...... findings here. Results Until 1997, DT104 infections made up less than 1 percent of all human salmonella infections. The strain isolated from patients in the first community outbreak of DT104 in Denmark, in 1998, was resistant to nalidixic acid and had reduced susceptibility to fluoroquinolones...... with fluoroquinolones. Conclusions Our investigation of an outbreak of DT104 documented the spread of quinolone-resistant bacteria from food animals to humans; this spread was associated with infections that were difficult to treat. Because of the increase in quinolone resistance in salmonella, the use...

  15. IDENTIFICATION OF UROVIRULENT MARKERS IN UROPATHOGE NIC ESCHERICHIA COLI.

    Directory of Open Access Journals (Sweden)

    Padmaja

    2012-10-01

    Full Text Available The present study was conducted in the Department o f Microbiology, Konaseema Institute of Medical Sciences, Amalapuram, East Goda vari District from August 2011 to January 2012. Fifty Escherichia coli (E.coli strains isola ted from urine samples of different clinical entities and 25 feacal isolates were studied for th e detection of virulence markers of E.coli. There are 27 uropathogenic E.coli (UPEC isolates fr om 50 E.coli & 5 UPEC from 25 controls. Among isolates tested the most common virulent mark er is haemolysin 21 (42%, followed by Mannose resistant haemagglutination 16 (32%, cell surface hydrophobicity 13 (26%. In this, there are 14 cases with only one virulence marker, 8 with 2 marker combinations and 15 cases with combination of 3 markers.

  16. EcoCyc: Encyclopedia of Escherichia coli genes and metabolism.

    Science.gov (United States)

    Karp, P D; Riley, M; Paley, S M; Pellegrini-Toole, A; Krummenacker, M

    1998-01-01

    The encyclopedia of Escherichia coli genes and metabolism (EcoCyc) is a database that combines information about the genome and the intermediary metabolism of E.coli. The database describes 3030 genes of E.coli , 695 enzymes encoded by a subset of these genes, 595 metabolic reactions that occur in E.coli, and the organization of these reactions into 123 metabolic pathways. The EcoCyc graphical user interface allows scientists to query and explore the EcoCyc database using visualization tools such as genomic-map browsers and automatic layouts of metabolic pathways. EcoCyc can be thought of as an electronic review article because of its copious references to the primary literature, and as a (qualitative) computational model of E.coli metabolism. EcoCyc is available at URL http://ecocyc.PangeaSystems.com/ecocyc/

  17. Phylogenetic Group Determination of Escherichia coli Isolated from Animals Samples

    Directory of Open Access Journals (Sweden)

    Fernanda Morcatti Coura

    2015-01-01

    Full Text Available This study analyzes the occurrence and distribution of phylogenetic groups of 391 strains of Escherichia coli isolated from poultry, cattle, and water buffalo. The frequency of the phylogroups was A = 19%, B1 = 57%, B2 = 2.3%, C = 4.6%, D = 2.8%, E = 11%, and F = 3.3%. Phylogroups A (P<0.001 and F (P=0.018 were associated with E. coli strains isolated from poultry, phylogroups B1 (P<0.001 and E (P=0.002 were associated with E. coli isolated from cattle, and phylogroups B2 (P=0.003 and D (P=0.017 were associated with E. coli isolated from water buffalo. This report demonstrated that some phylogroups are associated with the host analyzed and the results provide knowledge of the phylogenetic composition of E. coli from domestic animals.

  18. Mechanisms of quinolone resistance and implications for human and animal health

    Directory of Open Access Journals (Sweden)

    Velhner Maja

    2010-01-01

    Full Text Available Quinolone antibiotics have been widely used in human and veterinary medicine. This has caused the development of resistance and difficulties in the treatment of complicated bacterial infections in humans. The resistance to quinolones develops due to chromosome mutations and it can also be transferred by plasmids. The target enzyme for quinolones in Gram-negative bacteria is Gyrasa A, while the target enzyme in Grampositive bacteria is mostly topoisomerase IV. Gyrase A consists of two subunits encoded by genes gyrA and gyrB. The function of the enzyme is to introduce negative super coiling in DNA and therefore is essential for the replication of bacteria. Quinolone resistance develops if point mutations at 83 and/or 87 codon are introduced on gyrA. Establishing a minimal inhibitory concentration (MIC to this group of antimicrobials will reveal possible mutations. Recently it was discovered that quinolone resistance is transmittable by plasmid termed PMQR (plasmid mediated quinolone resistance. The target gene marked qnr encodes a pentapeptide repeat family protein. Pentapeptide repeats form sheets, involved in protein-protein interactions. Qnr protein binds to GyrA protecting the enzyme from the inhibitory effect of ciprofloxacin. The distribution of qnr related resistance is higher in humans than in animals. In poultry, however, this type of resistance is present more than in other animals. Plasmid mediated resistance contributes to the faster spread of quinolone resistance. Proper food handling will significantly contribute to decreasing the risk from infection to which people are exposed. In medical and veterinary laboratories antimicrobial resistance monitoring in clinical and environmental isolates is advised. Since correlation between antibiotics application and antimicrobial resistance is often suggested, antimicrobial use must be under strict control of the authorities both in human and in veterinary medicine. .

  19. Evolution of the iss gene in Escherichia coli.

    Science.gov (United States)

    Johnson, Timothy J; Wannemuehler, Yvonne M; Nolan, Lisa K

    2008-04-01

    The increased serum survival gene iss has long been recognized for its role in extraintestinal pathogenic Escherichia coli (ExPEC) virulence. iss has been identified as a distinguishing trait of avian ExPEC but not of human ExPEC. This gene has been localized to large virulence plasmids and shares strong similarities with the bor gene from bacteriophage lambda. Here, we demonstrate that three alleles of iss occur among E. coli isolates that appear to have evolved from a common lambda bor precursor. In addition to the occurrence of iss on the ColV/BM virulence plasmids, at least two iss alleles occur within the E. coli chromosome. One of these alleles (designated type 3) was found to occur in the genomes of all currently sequenced ExPEC strains on a similar prophage element that also harbors the Sit iron and manganese transport system. When the prevalence of the three iss types was examined among 487 E. coli isolates, the iss type 3 gene was found to occur at a high frequency among ExPEC isolates, irrespective of the host source. The plasmid-borne iss allele (designated type 1) was highly prevalent among avian pathogenic E. coli and neonatal meningitis-associated E. coli isolates but not among uropathogenic E. coli isolates. This study demonstrates the evolution of iss in E. coli and provides an additional tool for discriminating among E. coli pathotypes through the differentiation of the three iss allele types and bor.

  20. Persistent spread of the rmtB 16S rRNA methyltransferase gene among Escherichia coli isolates from diseased food-producing animals in China.

    Science.gov (United States)

    Xia, Jing; Sun, Jian; Cheng, Ke; Li, Liang; Fang, Liang-Xing; Zou, Meng-Ting; Liao, Xiao-Ping; Liu, Ya-Hong

    2016-05-30

    A total of 963 non-duplicate Escherichia coli strains isolated from food-producing animals between 2002 and 2012 were screened for the presence of the 16S rRNA methyltransferase genes. Among the positive isolates, resistance determinants to extended spectrum β-lactamases, plasmid-mediated quinolone resistance genes as well as floR and fosA/A3/C2 were detected using PCR analysis. These isolates were further subjected to antimicrobial susceptibility testing, molecular typing, PCR-based plasmid replicon typing and plasmid analysis. Of the 963 E. coli isolates, 173 (18.0%), 3 (0.3%) and 2 (0.2%) were rmtB-, armA- and rmtE-positive strains, respectively. All the 16S rRNA methyltransferase gene-positive isolates were multidrug resistant and over 90% of them carried one or more type of resistance gene. IncF (especially IncFII) and non-typeable plasmids played the main role in the dissemination of rmtB, followed by the IncN plasmids. Plasmids that harbored rmtB ranged in size from 20kb to 340kb EcoRI-RFLP testing of the 109 rmtB-positive plasmids from different years and different origins suggested that horizontal (among diverse animals) and vertical transfer of IncF, non-typeable and IncN-type plasmids were responsible for the spread of rmtB gene. In summary, our findings highlight that rmtB was the most prevalent 16S rRNA methyltransferase gene, which present persistent spread in food-producing animals in China and a diverse group of plasmids was responsible for rmtB dissemination.

  1. Widespread distribution of CTX-M and plasmid-mediated AmpC β-lactamases in Escherichia coli from Brazilian chicken meat

    Directory of Open Access Journals (Sweden)

    Larissa Alvarenga Batista Botelho

    2015-04-01

    Full Text Available The dissemination of plasmid-mediated antimicrobial resistance genes may pose a substantial public health risk. In the present work, the occurrences of blaCTX-M and plasmid-mediated ampC and qnr genes were investigated in Escherichia coli from 16 chicken carcasses produced by four commercial brands in Brazil. Of the brands tested, three were exporters, including one of organic chicken. Our study assessed 136 E. coli isolates that were grouped into 77 distinct biotypes defined by their origin, resistance profiling, the presence of β-lactamase and plasmid-mediated quinolone resistance genes and enterobacterial repetitive intergenic consensus-polimerase chain reaction typing. The blaCTX-M-15, blaCTX-M-2 and blaCTX-M-8 genes were detected in one, 17 and eight different biotypes, respectively (45 isolates. Twenty-one biotypes (46 isolates harboured blaCMY-2. Additionally, blaCMY-2 was identified in isolates that also carried either blaCTX-M-2 or blaCTX-M-8. The qnrB and/or qnrS genes occurred in isolates carrying each of the four types of β-lactamase determinants detected and also in oxyimino-cephalosporin-susceptible strains. Plasmid-mediated extended-spectrum β-lactamase (ESBL and AmpC determinants were identified in carcasses from the four brands tested. Notably, this is the first description of blaCTX-M-15 genes in meat or food-producing animals from South America. The blaCTX-M-8, blaCTX-M-15 and blaCMY-2 genes were transferable in conjugation experiments. The findings of the present study indicate that plasmid-mediated ESBL and AmpC-encoding genes are widely distributed in Brazilian chicken meat.

  2. Distinguishing importation from diversification of quinolone-resistant Neisseria gonorrhoeae by molecular evolutionary analysis

    Directory of Open Access Journals (Sweden)

    Dan Michael

    2007-06-01

    Full Text Available Abstract Background Distinguishing the recent introduction of quinolone resistant gonococci into a population from diversification of resistant strains already in the population is important for planning effective infection control strategies. We applied molecular evolutionary analyses to DNA sequences from 9 housekeeping genes and gyrA, parC and porB of 24 quinolone resistant N. gonorrhoeae (QRNG and 24 quinolone sensitive isolates collected in Israel during 2000–2001. Results Phylogenetic and eBURST analyses and estimates of divergence time indicated QRNG were introduced on 3 separate occasions and underwent limited diversification by mutation, deletion and horizontal gene transfer. Reconstruction of N. gonorrhoeae demography showed a slowly declining effective strain population size from 1976 to 1993, rapid decline between 1994 and 1999, and an increase from 1999 to 2001. This is partially attributable to declining gonorrhea case rates from 1973 to 1994. Additional contributing factors are selective sweeps of antibiotic resistant gonococci and increased transmission from sex workers. The abrupt decline in the mid-1990s heralded an increased incidence of gonorrhea from 1997 to the present. The subsequent increase in effective strain population size since 1999 reflects the increased gonococcal census population and introduction of quinolone resistance strains. Conclusion Our study demonstrates the effective use of population genetic approaches to assess recent and historical population dynamics of N. gonorrhoeae.

  3. Adhesive threads of extraintestinal pathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Antão Esther-Maria

    2009-12-01

    Full Text Available Abstract The ability to adhere to host surfaces is by far the most vital step in the successful colonization by microbial pathogens. Colonization begins with the attachment of the bacterium to receptors expressed by cells forming the lining of the mucosa. Long hair like extracellular appendages called fimbriae, produced by most Gram-negative pathogens, mediate specific attachment to the epithelial cell surface. Associated with the fimbriae is a protein called an adhesin, which directs high-affinity binding to specific cell surface components. In the last couple of years, an enormous amount of research has been undertaken that deals with understanding how bacterial pathogens adhere to host cells. E. coli in all probability is one of the best studied free-living organisms. A group of E. coli called Extraintestinal pathogenic E. coli (ExPEC including both human and animal pathogens like Uropathogenic E. coli (UPEC, Newborn meningitic E. coli (NMEC and Avian pathogenic E. coli (APEC, have been found to harbour many fimbriae including Type 1 fimbriae, P fimbriae, curli fibres, S fimbriae, F1C fimbriae, Dr fimbriae, afimbrial adhesins, temperature-sensitive haemagglutinin and many novel adhesin gene clusters that have not yet been characterized. Each of these adhesins is unique due to the recognition of an adhesin-specific receptor, though as a group these adhesins share common genomic organization. A newly identified putative adhesin temporarily termed ExPEC Adhesin I, encoded by gene yqi, has been recently found to play a significant role in the pathogenesis of APEC infection, thus making it an interesting candidate for future research. The aim of this review is to describe the role of ExPEC adhesins during extraintestinal infections known till date, and to suggest the idea of investigating their potential role in the colonization of the host gut which is said to be a reservoir for ExPEC.

  4. Deuterium incorporation into Escherichia-coli proteins

    DEFF Research Database (Denmark)

    Lederer, H.; May, R. P.; Kjems, Jørgen

    1986-01-01

    Neutron small-angle scattering studies of single protein subunits in a protein-DNA complex require the adjustment of the neutron scattering-length densities of protein and DNA, which is attainable by specific deuteration of the protein. The neutron scattering densities of unlabelled DNA and DNA...... of the degree of deuteration and match point of any E. coli protein from the D2O content of the growth medium, taking the 2H incorporation into RNA polymerase amino acids to be representative for all amino acids in E. coli proteins. The small-angle scattering results, on which the calculation of the degree...

  5. Deuterium incorporation into Escherichia-coli proteins

    DEFF Research Database (Denmark)

    Lederer, H.; May, R. P.; Kjems, Jørgen;

    1986-01-01

    Neutron small-angle scattering studies of single protein subunits in a protein-DNA complex require the adjustment of the neutron scattering-length densities of protein and DNA, which is attainable by specific deuteration of the protein. The neutron scattering densities of unlabelled DNA and DNA...... of the degree of deuteration and match point of any E. coli protein from the D2O content of the growth medium, taking the 2H incorporation into RNA polymerase amino acids to be representative for all amino acids in E. coli proteins. The small-angle scattering results, on which the calculation of the degree...

  6. Infectious endocarditis caused by Escherichia coli

    DEFF Research Database (Denmark)

    Lauridsen, Trine Kiilerich; Arpi, Magnus; Fritz-Hansen, Thomas

    2011-01-01

    -spectrum intravenous antibiotics. Transthoracic and transoesophageal echocardiography revealed a severe mitral endocarditis. E. coli DNA was identified from the mitral valve and the vegetation, and no other pathogen was found. The case was further complicated by spondylodiscitis and bilateral endophthalmitis. Extra...

  7. Genomic Comparative Study of Bovine Mastitis Escherichia coli

    Science.gov (United States)

    Kempf, Florent; Slugocki, Cindy; Blum, Shlomo E.; Leitner, Gabriel; Germon, Pierre

    2016-01-01

    Escherichia coli, one of the main causative agents of bovine mastitis, is responsible for significant losses on dairy farms. In order to better understand the pathogenicity of E. coli mastitis, an accurate characterization of E. coli strains isolated from mastitis cases is required. By using phylogenetic analyses and whole genome comparison of 5 currently available mastitis E. coli genome sequences, we searched for genotypic traits specific for mastitis isolates. Our data confirm that there is a bias in the distribution of mastitis isolates in the different phylogenetic groups of the E. coli species, with the majority of strains belonging to phylogenetic groups A and B1. An interesting feature is that clustering of strains based on their accessory genome is very similar to that obtained using the core genome. This finding illustrates the fact that phenotypic properties of strains from different phylogroups are likely to be different. As a consequence, it is possible that different strategies could be used by mastitis isolates of different phylogroups to trigger mastitis. Our results indicate that mastitis E. coli isolates analyzed in this study carry very few of the virulence genes described in other pathogenic E. coli strains. A more detailed analysis of the presence/absence of genes involved in LPS synthesis, iron acquisition and type 6 secretion systems did not uncover specific properties of mastitis isolates. Altogether, these results indicate that mastitis E. coli isolates are rather characterized by a lack of bona fide currently described virulence genes. PMID:26809117

  8. Genomic Comparative Study of Bovine Mastitis Escherichia coli.

    Science.gov (United States)

    Kempf, Florent; Slugocki, Cindy; Blum, Shlomo E; Leitner, Gabriel; Germon, Pierre

    2016-01-01

    Escherichia coli, one of the main causative agents of bovine mastitis, is responsible for significant losses on dairy farms. In order to better understand the pathogenicity of E. coli mastitis, an accurate characterization of E. coli strains isolated from mastitis cases is required. By using phylogenetic analyses and whole genome comparison of 5 currently available mastitis E. coli genome sequences, we searched for genotypic traits specific for mastitis isolates. Our data confirm that there is a bias in the distribution of mastitis isolates in the different phylogenetic groups of the E. coli species, with the majority of strains belonging to phylogenetic groups A and B1. An interesting feature is that clustering of strains based on their accessory genome is very similar to that obtained using the core genome. This finding illustrates the fact that phenotypic properties of strains from different phylogroups are likely to be different. As a consequence, it is possible that different strategies could be used by mastitis isolates of different phylogroups to trigger mastitis. Our results indicate that mastitis E. coli isolates analyzed in this study carry very few of the virulence genes described in other pathogenic E. coli strains. A more detailed analysis of the presence/absence of genes involved in LPS synthesis, iron acquisition and type 6 secretion systems did not uncover specific properties of mastitis isolates. Altogether, these results indicate that mastitis E. coli isolates are rather characterized by a lack of bona fide currently described virulence genes.

  9. Chromosomal features of Escherichia coli serotype O2:K2, an avian pathogenic E. coli.

    Science.gov (United States)

    Jørgensen, Steffen L; Kudirkiene, Egle; Li, Lili; Christensen, Jens P; Olsen, John E; Nolan, Lisa; Olsen, Rikke H

    2017-01-01

    Escherichia coli causing infection outside the gastrointestinal system are referred to as extra-intestinal pathogenic E. coli. Avian pathogenic E. coli is a subgroup of extra-intestinal pathogenic E. coli and infections due to avian pathogenic E. coli have major impact on poultry production economy and welfare worldwide. An almost defining characteristic of avian pathogenic E. coli is the carriage of plasmids, which may encode virulence factors and antibiotic resistance determinates. For the same reason, plasmids of avian pathogenic E. coli have been intensively studied. However, genes encoded by the chromosome may also be important for disease manifestation and antimicrobial resistance. For the E. coli strain APEC_O2 the plasmids have been sequenced and analyzed in several studies, and E. coli APEC_O2 may therefore serve as a reference strain in future studies. Here we describe the chromosomal features of E. coli APEC_O2. E. coli APEC_O2 is a sequence type ST135, has a chromosome of 4,908,820 bp (plasmid removed), comprising 4672 protein-coding genes, 110 RNA genes, and 156 pseudogenes, with an average G + C content of 50.69%. We identified 82 insertion sequences as well as 4672 protein coding sequences, 12 predicated genomic islands, three prophage-related sequences, and two clustered regularly interspaced short palindromic repeats regions on the chromosome, suggesting the possible occurrence of horizontal gene transfer in this strain. The wildtype strain of E. coli APEC_O2 is resistant towards multiple antimicrobials, however, no (complete) antibiotic resistance genes were present on the chromosome, but a number of genes associated with extra-intestinal disease were identified. Together, the information provided here on E. coli APEC_O2 will assist in future studies of avian pathogenic E. coli strains, in particular regarding strain of E. coli APEC_O2, and aid in the general understanding of the pathogenesis of avian pathogenic E. coli.

  10. Alterations induced in Escherichia Coli cells by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kappke, J.; Schelin, H.R.; Paschuk, S.A.; Denyak, V.; Silva, E.R. da [Federal University of Technology of Parana (CPGEI/UTFPR), Curitiba, PR (Brazil)]. E-mails: jaquekap@yahoo.com.br; schelin@cpgei.cefetpr.br; sergei@utfpr.edu.br; Jesus, E.F.O. de; Lopes, R.T. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Instrumentacao Nuclear]. E-mails: ricardo@lin.ufrj.br; edgar@lin.ufrj.br; Carlin, N.; Toledo, E.S. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Fisica]. E-mail: nelson.carlin@dfn.if.usp.br

    2007-07-01

    Modifications occurred in Escherichia coli cells exposed to gamma radiation ({sup 60}Co source) were investigated. The irradiations were done at the LIN-COPPE laboratory of the UFRJ and the analysis at the Biology Department of the UTFPR. The E. coli cells were irradiated with 30, 60, 90, 120, 150, 180, 210, 240, 300, 480, 600 e 750 Gy doses. The samples were analyzed with Gram-stain, biochemical tests in EPM, MIO and Lysine Broth, Simmons Cytrate Medium and Rhamnose Broth, antibiogram and isolation of auxotrophic mutants. It was observed that for the received doses the E. coli did not show morphological alterations in the tests. Some E. Coli cells showed to be able to deaminade the L-tryptophan or they changed their sensibility for amoxillin and cephaloonine after the irradiation. The existence of aauxotrophic mutants after irradiation was also verified. (author)

  11. Is Escherichia coli urinary tract infection a zoonosis?

    DEFF Research Database (Denmark)

    Jacobsen, L.; Garneau, P.; Bruant, G.

    2012-01-01

    and kidney cultures. Further, isolates with the same gene profile also yielded similar bacterial counts in urine, bladder and kidneys. This study showed a clonal link between E. coli from meat and humans, providing solid evidence that UTI is zoonosis. The close relationship between community-dwelling human......Recently, it has been suggested that the Escherichia coli causing urinary tract infection (UTI) may come from meat and animals. The purpose was to investigate if a clonal link existed between E. coli from animals, meat and UTI patients. Twenty-two geographically and temporally matched B2 E. coli...... from UTI patients, community-dwelling humans, broiler chicken meat, pork, and broiler chicken, previously identified to exhibit eight virulence genotypes by microarraydetection of approximately 300 genes, were investigated for clonal relatedness by PFGE. Nine isolates were selected and tested...

  12. Occurrence of pathogenic and faecal Escherichia coli in layer hens

    Directory of Open Access Journals (Sweden)

    Silvia Tagliabue

    2010-01-01

    Full Text Available A total of 117 Escherichia coli from colibacillosis affected (APEC and clinically healthy birds (AFEC were serotyped and tested for the presence of virulence genes: iss, tsh, cva. A total of 54.5% E. Coli were typeable and 15 different serogroups were identified. The most common serogroups among APEC strains were O78, O2 and O128, whereas O139 was predominant in faecal strains from healthy birds. Iss, tsh e cva were more frequently detected among the septicaemic E. coli strains. The association of virulence genes was observed. Particularly, the pathotype iss-tsh-cva was present in 46.5% of APEC strains. Referring to serogroups, E. coli O78 and O2 originating from colibacillosis affected birds were always isstsh- cva positive but did not share virulence genes when they came from healthy birds.

  13. EcoCyc: Enyclopedia of Escherichia coli Genes and Metabolism.

    Science.gov (United States)

    Karp, P D; Riley, M; Paley, S M; Pellegrini-Toole, A; Krummenacker, M

    1997-01-01

    The Encyclopedia of Genes and Metabolism (EcoCyc) is a database that combines information about the genome and the intermediary metabolism of Escherichia coli. It describes 2970 genes of E.coli, 547 enzymes encoded by these genes, 702 metabolic reactions that occur in E.coli and the organization of these reactions into 107 metabolic pathways. The EcoCyc graphical user interface allows scientists to query and explore the EcoCyc database using visualization tools such as genomic-map browsers and automatic layouts of metabolic pathways. EcoCyc spans the space from sequence to function to allow scientists to investigate an unusually broad range of questions. EcoCyc can be thought of as both an electronic review article because of its copious references to the primary literature, and as an in silicio model of E.coli metabolism that can be probed and analyzed through computational means.

  14. Escherichia coli control in a surface flow treatment wetland.

    Science.gov (United States)

    MacIntyre, M E; Warner, B G; Slawson, R M

    2006-06-01

    A field experiment showed that numbers of Escherichia coli declined significantly when floating Lemna spp. plants were removed to create open water areas in a typical newly constructed surface flow treatment wetland in southern Ontario. It is suggested that E. coli declined immediately after Lemna removal because the Lemna was shading the water column from penetration by natural UV radiation, it was providing favourable attachment sites for the E. coli, and it was not allowing effective free exchange of oxygen from surface winds to the water column to maintain high enough dissolved oxygen supplies for predator zooplankton populations. Operators of wetland systems must have the specialized skills required to recognize the cause and the appropriate maintenance requirements to maintain efficient operation of such unconventional systems should E. coli numbers increase during the course of operation.

  15. Engineered synthetic pathway for isopropanol production in Escherichia coli.

    Science.gov (United States)

    Hanai, T; Atsumi, S; Liao, J C

    2007-12-01

    A synthetic pathway was engineered in Escherichia coli to produce isopropanol by expressing various combinations of genes from Clostridium acetobutylicum ATCC 824, E. coli K-12 MG1655, Clostridium beijerinckii NRRL B593, and Thermoanaerobacter brockii HTD4. The strain with the combination of C. acetobutylicum thl (acetyl-coenzyme A [CoA] acetyltransferase), E. coli atoAD (acetoacetyl-CoA transferase), C. acetobutylicum adc (acetoacetate decarboxylase), and C. beijerinckii adh (secondary alcohol dehydrogenase) achieved the highest titer. This strain produced 81.6 mM isopropanol in shake flasks with a yield of 43.5% (mol/mol) in the production phase. To our knowledge, this work is the first to produce isopropanol in E. coli, and the titer exceeded that from the native producers.

  16. Biosynthesis of Two Flavones, Apigenin and Genkwanin, in Escherichia coli.

    Science.gov (United States)

    Lee, Hyejin; Kim, Bong Gyu; Kim, Mihyang; Ahn, Joong-Hoon

    2015-09-01

    The flavonoid apigenin and its O-methyl derivative, genkwanin, have various biological activities and can be sourced from some vegetables and fruits. Microorganisms are an alternative for the synthesis of flavonoids. Here, to synthesize genkwanin from tyrosine, we first synthesized apigenin from p-coumaric acid using four genes (4CL, CHS, CHI, and FNS) in Escherichia coli. After optimization of different combinations of constructs, the yield of apigenin was increased from 13 mg/l to 30 mg/l. By introducing two additional genes (TAL and POMT7) into an apigenin-producing E. coli strain, we were able to synthesize 7-O-methyl apigenin (genkwanin) from tyrosine. In addition, the tyrosine content in E. coli was modulated by overexpressing aroG and tyrA. The engineered E. coli strain synthesized approximately 41 mg/l genkwanin.

  17. Yeast DNA sequences initiating gene expression in Escherichia coli.

    Science.gov (United States)

    Lewin, Astrid; Tran, Thi Tuyen; Jacob, Daniela; Mayer, Martin; Freytag, Barbara; Appel, Bernd

    2004-01-01

    DNA transfer between pro- and eukaryotes occurs either during natural horizontal gene transfer or as a result of the employment of gene technology. We analysed the capacity of DNA sequences from a eukaryotic donor organism (Saccharomyces cerevisiae) to serve as promoter region in a prokaryotic recipient (Escherichia coli) by creating fusions between promoterless luxAB genes from Vibrio harveyi and random DNA sequences from S. cerevisiae and measuring the luminescence of transformed E. coli. Fifty-four out of 100 randomly analysed S. cerevisiae DNA sequences caused considerable gene expression in E. coli. Determination of transcription start sites within six selected yeast sequences in E. coli confirmed the existence of bacterial -10 and -35 consensus sequences at appropriate distances upstream from transcription initiation sites. Our results demonstrate that the probability of transcription of transferred eukaryotic DNA in bacteria is extremely high and does not require the insertion of the transferred DNA behind a promoter of the recipient genome.

  18. Food-borne origins of Escherichia coli causing extraintestinal infections.

    Science.gov (United States)

    Manges, Amee R; Johnson, James R

    2012-09-01

    Most human extraintestinal Escherichia coli infections, including those involving antimicrobial resistant strains, are caused by the members of a limited number of distinctive E. coli lineages, termed extraintestinal pathogenic E. coli (ExPEC), that have a special ability to cause disease at extraintestinal sites when they exit their usual reservoir in the host's intestinal tract. Multiple lines of evidence suggest that many of the ExPEC strains encountered in humans with urinary tract infection, sepsis, and other extraintestinal infections, especially the most extensively antimicrobial-resistant strains, may have a food animal source, and may be transmitted to humans via the food supply. This review summarizes the evidence that food-borne organisms are a significant cause of extraintestinal E. coli infections in humans.

  19. Effect of Genetic Database Comprehensiveness on Fractional Proteomics of Escherichia coli O157:H7

    Science.gov (United States)

    2014-01-01

    EFFECT OF GENETIC DATABASE COMPREHENSIVENESS ON FRACTIONAL PROTEOMICS OF ESCHERICHIA COLI O157:H7 ECBC-TR-1154...Database Comprehensiveness on Fractional Proteomics of Escherichia coli O157:H7 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...are characterizing the extracellular, fimbriae, and whole cell proteins produced by the pathogenic Gram-negative bacterium Escherichia coli (E. coli

  20. QnrS1- and Aac(6’-Ib-cr-producing Escherichia coli among isolates from animals of different sources: susceptibility and genomic characterization

    Directory of Open Access Journals (Sweden)

    Daniela eJones-Dias

    2016-05-01

    Full Text Available Salmonella enterica and Escherichia coli can inhabit humans and animals from multiple origins. These bacteria are often associated with gastroenteritis in animals, being a frequent cause of resistant zoonotic infections. In fact, bacteria from animals can be transmitted to humans through the food chain and direct contact. In this study, we aimed to assess the antibiotic susceptibility of a collection of S. enterica and E. coli recovered from animals of different sources, performing a genomic comparison of the plasmid-mediated quinolone resistance (PMQR-producing isolates detected.Antibiotic susceptibility testing revealed a high number of non wild-type isolates for fluoroquinolones among S. enterica recovered from poultry isolates. In turn, the frequency of non-wild-type E. coli to nalidixic acid and ciprofloxacin was higher in food-producing animals than in companion or zoo animals. Globally, we detected two qnrS1 and two aac(6’-Ib-cr in E. coli isolates recovered from animals of different origins. The genomic characterization of QnrS1-producing E. coli showed high genomic similarity (O86:H12 and ST2297, although they have been recovered from a healthy turtle dove from a Zoo Park, and from a dog showing symptoms of infection. The qnrS1 gene was encoded in a IncN plasmid, also carrying blaTEM-1-containing Tn3. Isolates harboring aac(6’-Ib-cr were detected in two captive bottlenose dolphins, within a time span of two years. The additional antibiotic resistance genes of the two aac(6’-Ib-cr-positive isolates (blaOXA-1, blaTEM-1, blaCTX-M-15, catB3, aac(3-IIa and tetA were enclosed in IncFIA plasmids that differed in a single transposase and 60 single nucleotide variants. The isolates could be assigned to the same genetic sublineage – ST131 fimH30-Rx (O25:H4, confirming clonal spread. PMQR-producing isolates were associated with symptomatic and asymptomatic hosts, which highlight the aptitude of E. coli to act as silent vehicles, allowing

  1. Viabilidad de Escherichia coli en presencia De diferentes contaminantes

    OpenAIRE

    Antonio Rivera T,; Edith Chávez B.; Gisela Rendón A.; Silvia Giono C

    2006-01-01

    La contaminación en ríos condiciona la presencia de microorganismos adaptados al ecosistema entre ellos a pató-genos de importancia en salud pública. Objetivo: Determinar la viabilidad de Escherichia coli en presencia de nitrato de plata, carbonato de amonio, fenol y formaldehído. Materiales y métodos: Se tomaron muestras de agua del río Alseseca, que luego se sembró en medios de cultivo selectivos para enterobacterias, seleccionándose las colonias del género Escherichia, las cuales fueron se...

  2. Overcoming target-mediated quinolone resistance in topoisomerase IV by introducing metal-ion-independent drug-enzyme interactions.

    Science.gov (United States)

    Aldred, Katie J; Schwanz, Heidi A; Li, Gangqin; McPherson, Sylvia A; Turnbough, Charles L; Kerns, Robert J; Osheroff, Neil

    2013-12-20

    Quinolones, which target gyrase and topoisomerase IV, are the most widely prescribed antibacterials worldwide. Unfortunately, their use is threatened by the increasing prevalence of target-mediated drug resistance. Greater than 90% of mutations that confer quinolone resistance act by disrupting enzyme-drug interactions coordinated by a critical water-metal ion bridge. Quinazolinediones are quinolone-like drugs but lack the skeletal features necessary to support the bridge interaction. These compounds are of clinical interest, however, because they retain activity against the most common quinolone resistance mutations. We utilized a chemical biology approach to determine how quinazolinediones overcome quinolone resistance in Bacillus anthracis topoisomerase IV. Quinazolinediones that retain activity against quinolone-resistant topoisomerase IV do so primarily by establishing novel interactions through the C7 substituent, rather than the drug skeleton. Because some quinolones are highly active against human topoisomerase IIα, we also determined how clinically relevant quinolones discriminate between the bacterial and human enzymes. Clinically relevant quinolones display poor activity against topoisomerase IIα because the human enzyme cannot support drug interactions mediated by the water-metal ion bridge. However, the inclusion of substituents that allow quinazolinediones to overcome topoisomerase IV-mediated quinolone resistance can cause cross-reactivity against topoisomerase IIα. Therefore, a major challenge in designing drugs that overcome quinolone resistance lies in the ability to identify substituents that mediate strong interactions with the bacterial, but not the human, enzymes. On the basis of our understanding of quinolone-enzyme interactions, we have identified three compounds that display high activity against quinolone-resistant B. anthracis topoisomerase IV but low activity against human topoisomerase IIα.

  3. Circular dimers of lambda DNA in infected, nonlysogenic Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Freifelder, D.; Baran, N.; Folkmanis, A.; Freifelder, D.L.R.

    1977-09-01

    Covalently closed circular dimerss of phage lambda DNA have been found in Escherichia coli infected with lambda. These dimers can be formed by either the lambda Red or Int systems, by a nonrecombinational replicative mechanism requiring the activity of the lambda O and P genes or by joining of the cohesive ends. Dimers mediated by the E. coli Rec system have not been observed. Those formed by the Int system often result from recombination between different DNA molecules; however, the Red-mediated dimer may be a result of replicative extension of a single DNA molecule. Trimers have also been observed but studied only briefly.

  4. Enteropathogenic Escherichia coli Serotypes and Endemic Diarrhea in Infants

    OpenAIRE

    M. Regina F. Toledo; Alvariza, M. do Carmo B.; Murahovschi, Jayme; Sonia R.T.S. RAMOS; Trabulsi, Luiz R.

    1983-01-01

    Enteropathogenic Escherichia coli serotypes were searched for in feces of 550 children with endemic diarrhea and in 129 controls, in São Paulo, in 1978 and 1979; serotypes O111ab:H−, O111ab:H2, and O119:H6 were significantly associated with diarrhea in children 0 to 5 months old and were the most frequent agents of diarrhea in this age group as compared with enterotoxigenic and enteroinvasive E. coli, Salmonella sp., Shigella sp., and Yersinia enterocolitica. It is concluded that various ente...

  5. Sedimentation and gravitational instability of Escherichia coli Suspension

    Science.gov (United States)

    Douarche, Carine; Salin, Dominique; Collaboration between Laboratory FAST; LPS Collaboration

    2016-11-01

    The successive run and tumble of Escherichia coli bacteria provides an active matter suspension of rod-like particles with a large swimming diffusion. As opposed to inactive elongated particles, this diffusion prevents clustering and instability in the gravity field. We measure the time dependent E . coli concentration profile during their sedimentation. After some hours, due to the dioxygen consumption, a motile / non-motile front forms leading to a Rayleigh-Taylor type gravitational instability. Analyzing both sedimentation and instability in the framework of active particle suspensions, we can measure the relevant bacteria hydrodynamic characteristics such as its single particle sedimentation velocity and its hindrance volume.

  6. [Drug resistance of Escherichia coli strains isolated from poultry].

    Science.gov (United States)

    Giurov, B; Korudzhiĭski, N; Bineva, I

    1981-01-01

    Studied was the sensitivity of a total of 143 strains of Escherichia coli, isolated from young birds and broilers died from coli septicaemia, to antibiotics and chemotherapeutics. The following descending order was established: gentamycin, carbenicillin, ampicillin, furazolidon, borgal, kanamycin, strep tomycin, chloramphenicol, neomycin sulphathiazole, and tetracycline. Markers of resistance were established with all strains with regard to the therapeutic agents in current and prospective use in industrial poultry farming. It is stated that a preliminary antibiogram is indispensable in order to obtain dependable results in the treatment of animals affected with colibacteriosis. An alternative is to apply directly those drugs to which the strains have shown highest sensitivity.

  7. Inducible repair of oxidative DNA damage in Escherichia coli.

    Science.gov (United States)

    Demple, B; Halbrook, J

    Hydrogen peroxide is lethal to many cell types, including the bacterium Escherichia coli. Peroxides yield transient radical species that can damage DNA and cause mutations. Such partially reduced oxygen species are occasionally released during cellular respiration and are generated by lethal and mutagenic ionizing radiation. Because cells live in an environment where the threat of oxidative DNA damage is continual, cellular mechanisms may have evolved to avoid and repair this damage. Enzymes are known which evidently perform these functions. We report here that resistance to hydrogen peroxide toxicity can be induced in E. coli, that this novel induction is specific and occurs, in part, at the level of DNA repair.

  8. Antibacterial behavior of diamond nanoparticles against Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Beranova, Jana; Seydlova, Gabriela [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 16200 Prague (Czech Republic); Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Vinicna 5, 12844 Prague (Czech Republic); Kozak, Halyna; Potocky, Stepan; Kromka, Alexander [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 16200 Prague (Czech Republic); Konopasek, Ivo [Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Vinicna 5, 12844 Prague (Czech Republic)

    2012-12-15

    In this study, we investigated the potential antibacterial properties of nanocrystalline diamond. In particular, we tested the effect of diamond nanoparticles (DNPs) on growth of the model gram-negative bacterium Escherichia coli on solid, nutrient-rich growth medium. We found that the presence of DNPs on agar plates significantly reduced the colony forming ability of E. coli. The antibacterial effect occurred in a concentration dependent manner and was conditional on the specific ratio of DNPs to the number of bacterial cells. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. ESCHERICHIA COLI: AN IMPORTANT PATHOGEN IN PATIENTS WITH HEMATOLOGIC MALIGNANCIES

    Directory of Open Access Journals (Sweden)

    Daniel Olson

    2014-08-01

    Full Text Available Abstract Background Escherichia coli (E. coli is a pathogen of great concern in immunosuppressed patients.  While antimicrobial prophylactic therapy has become the standard, the emergence of resistant pathogens has some questioning its use.  This study describes our experience with E.coli as a pathogen in neutropenic patients with a hematologic malignancy, and addresses future directions of treatment for this patient population. Methods A retrospective chart review of 245 E.coli bacteremia patients at Moffitt Cancer Center from 05/18/02 – 05/15/12 was conducted. Patients were identified via microbiology laboratory computerized records. Results The included patients experienced clinically significant E.coli bacteremia resulting in a median hospital stay of 14.7 days.  Several patients developed severe sepsis requiring the use of pressor and ventilator therapy. Conclusions E.coli is a major pathogen in these patient populations resulting in extended hospital stays and specialized treatment to overcome their E.coli bacteremia. The data supports the use of fluoroquinolone prophylactic therapy, however, earlier detection and treatment of neutropenic infection is needed.

  10. Gentamicin resistance among Escherichia coli strains isolated in neonatal sepsis.

    Science.gov (United States)

    Hasvold, J; Bradford, L; Nelson, C; Harrison, C; Attar, M; Stillwell, T

    2013-01-01

    Neonatal sepsis is a significant cause of morbidity and mortality among term and preterm infants. Ampicillin and gentamicin are standard empiric therapy for early onset sepsis. Four cases of neonatal sepsis secondary to Escherichia coli (E. coli) found to be gentamicin resistant occurred within a five week period in one neonatal intensive care unit (NICU). To determine whether these cases could be tied to a single vector of transmission, and to more broadly evaluate the incidence of gentamicin resistant strains of E. coli in the neonatal population at our institution compared to other centers, we reviewed the charts of the four neonates (Infants A through D) and their mothers. The E. coli isolates were sent for Pulse Field Gel Electrophoresis (PFGE) to evaluate for genetic similarity between strains. We also reviewed all positive E. coli cultures from one NICU over a two year period. Infants A and B had genetically indistinguishable strains which matched that of urine and placental cultures of Infant B's mother. Infant C had a genetically distinct organism. Infant D, the identical twin of Infant C, did not have typing performed. Review of all cultures positive for E. coli at our institution showed a 12.9 percent incidence of gentamicin-resistance. A review of other studies showed that rates of resistance vary considerably by institution. We conclude that gentamicin-resistant E. coli is a relatively uncommon cause of neonatal sepsis, but should remain a consideration in patients who deteriorate despite initiation of empiric antibiotics.

  11. EFFECT OF VISIBLE RANGE ELECTROMAGNETIC RADIATIONS ON ESCHERICHIA COLI.

    Science.gov (United States)

    Azeemi, Samina T Yousuf; Shaukat, Saleem Farooq; Azeemi, Khawaja Shamsuddin; Khan, Idrees; Mahmood, Khalid; Naz, Farah

    2017-01-01

    Escherichia coli is the agent responsible for a range of clinical diseases. With emerging antimicrobial resistance, other treatment options including solar/photo-therapy are becoming increasingly common. Visible Range Radiation Therapy/Colour Therapy is an emerging technique in the field of energy/vibrational medicine that uses visible spectrum of Electromagnetic Radiations to cure different diseases. In this study, our goal was to understand the effect of Visible Range Electromagnetic Radiations on E. coli (in vitro) and therefore find out the most appropriate visible range radiation for the treatment of diseases caused by E. coli. A total of 6 non-repetitive E. coli isolates were obtained from urine samples obtained from hospitalized patients with UTI. Single colony of E. coli was inoculated in 3 ml of Lysogeny Broth (LB) and 40 μl of this E. coli suspension was poured into each of the plastic tubes which were then irradiated with six different wavelengths in the visible region (Table. 1) after 18 hours with one acting as a control. The Optical Densities of these irradiated samples were then measured. Furthermore, scanning electron microscopy (TEFCAN ZEGA3) was carried out. The analysis of the microscopic and SEM images of irradiated E. coli samples with six different visible range radiations is representative of The fact that E. coli responded differently to every applied radiation in the visible region and the most profound inhibitory effects were that of 538nm Visible Range Radiation (Green) which proved to be bactericidal and 590nm Visible Range Radiation (yellow) which was bacteriostatic. The enhanced growth of E. coli with varying degrees was clearly observed in 610nm (orange), 644nm (red), 464nm (Purple) and 453nm (blue). It can be concluded that 538nm (Green) and 590nm (Yellow) can effectively be used for treating E. coli borne diseases.

  12. Stimulation of Escherichia coli F-18Col- Type-1 fimbriae synthesis by leuX

    DEFF Research Database (Denmark)

    Newman, Joseph V.; Burghoff, Robert L.; Pallesen, Lars

    1994-01-01

    Escherichia coli F-18, a normal human fecal isolate, is an excellent colonizer of the streptomycin-treated mouse large intestine. E. coli F-18Col-, a derivative of E. coli F-18 which no longer makes the E. coli F-18 colicin, colonizes the large intestine as well as E. coli F-18 when fed to mice a...

  13. Comparison of 61 Sequenced Escherichia coli Genomes

    DEFF Research Database (Denmark)

    Lukjancenko, Oksana; Wassenaar, T. M.; Ussery, David

    2010-01-01

    MLST was performed, many of the various strains appear jumbled and less well resolved. The predicted pan-genome comprises 15,741 gene families, and only 993 (6%) of the families are represented in every genome, comprising the core genome. The variable or 'accessory' genes thus make up more than 90......% of the pan-genome and about 80% of a typical genome; some of these variable genes tend to be co-localized on genomic islands. The diversity within the species E. coli, and the overlap in gene content between this and related species, suggests a continuum rather than sharp species borders in this group...

  14. Biogenesis of inner membrane proteins in Escherichia coli.

    Science.gov (United States)

    Luirink, Joen; Yu, Zhong; Wagner, Samuel; de Gier, Jan-Willem

    2012-06-01

    The inner membrane proteome of the model organism Escherichia coli is composed of inner membrane proteins, lipoproteins and peripherally attached soluble proteins. Our knowledge of the biogenesis of inner membrane proteins is rapidly increasing. This is in particular true for the early steps of biogenesis - protein targeting to and insertion into the membrane. However, our knowledge of inner membrane protein folding and quality control is still fragmentary. Furthering our knowledge in these areas will bring us closer to understand the biogenesis of individual inner membrane proteins in the context of the biogenesis of the inner membrane proteome of Escherichia coli as a whole. This article is part of a Special Issue entitled: Biogenesis/Assembly of Respiratory Enzyme Complexes.

  15. Tranformasi Fragmen Dna Kromosom Xanthomonas Campestris ke dalam Escherichia Coli

    Directory of Open Access Journals (Sweden)

    Wibowo Mangunwardoyo

    2002-04-01

    Full Text Available Research on DNA transformation of Xanthomonas campestris into Escherichia coli DH5αα using plasmid vector Escherichia coli (pUC19. was carried out. DNA chromosome was isolated using CTAB method, alkali lysis method was used to isolate DNA plasmid. Both of DNA plasmid and chromosome were digested using restriction enzyme EcoRI. Competent cell was prepared with CaCl2 and heat shock method for transformation procedure. The result revealed transformation obtain 5 white colonies, with transformation frequency was 1,22 x 10-8 colony/competent cell. Electrophoresis analysis showed the DNA fragment (insert in range 0.5 – 7,5 kb. Further research should be carried out to prepare the genomic library to obtain better result of transformant.

  16. Mechanobiology of Antimicrobial Resistant Escherichia coli and Listeria innocua.

    Science.gov (United States)

    Tajkarimi, Mehrdad; Harrison, Scott H; Hung, Albert M; Graves, Joseph L

    2016-01-01

    A majority of antibiotic-resistant bacterial infections in the United States are associated with biofilms. Nanoscale biophysical measures are increasingly revealing that adhesive and viscoelastic properties of bacteria play essential roles across multiple stages of biofilm development. Atomic Force Microscopy (AFM) applied to strains with variation in antimicrobial resistance enables new opportunities for investigating the function of adhesive forces (stickiness) in biofilm formation. AFM force spectroscopy analysis of a field strain of Listeria innocua and the strain Escherichia coli K-12 MG1655 revealed differing adhesive forces between antimicrobial resistant and nonresistant strains. Significant increases in stickiness were found at the nanonewton level for strains of Listeria innocua and Escherichia coli in association with benzalkonium chloride and silver nanoparticle resistance respectively. This advancement in the usage of AFM provides for a fast and reliable avenue for analyzing antimicrobial resistant cells and the molecular dynamics of biofilm formation as a protective mechanism.

  17. Specific mistranslation in hisT mutants of Escherichia coli.

    Science.gov (United States)

    Parker, J

    1982-01-01

    Certain strains of Escherichia coli mistranslate at very high frequencies when starved for asparagine or histidine. This mistranslation is the result of misreading events on the ribosome. The introduction of a hisT mutation into such a strain decreases the frequency of mistranslation during histidine starvation but not during asparagine starvation. The most likely explanation is that the replacement of the pseudouridine residue in the anticodon loop of glutamine specific transfer ribonucleic acid by uridine in hisT mutants leads to an increase in fidelity of transfer ribonucleic acid function. The hisT gene in Escherichia coli has also been more accurately mapped, giving the gene order purF-hisT-aroC-fadL-dsdA.

  18. Co-infection of methicillin-resistant Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus and extended spectrum β-lactamase producing Escherichia coli in bovine mastitis--three cases reported from India.

    Science.gov (United States)

    Bandyopadhyay, Samiran; Samanta, Indranil; Bhattacharyya, Debaraj; Nanda, Pramod Kumar; Kar, Debasish; Chowdhury, Jayanta; Dandapat, Premanshu; Das, Arun Kumar; Batul, Nayan; Mondal, Bimalendu; Dutta, Tapan Kumar; Das, Gunjan; Das, Bikash Chandra; Naskar, Syamal; Bandyopadhyay, Uttam Kumar; Das, Suresh Chandra; Bandyopadhyay, Subhasish

    2015-03-01

    Emergence of antimicrobial resistance among bovine mastitis pathogens is the major cause of frequent therapeutic failure and a cause of concern for veterinary practitioners. This study describes intra-mammary infection of methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum β-lactamase (ESBL) producing Escherichia coli in two Holstein Friesian crossbred cows with subclinical mastitis and one non-descript cow with clinical mastitis in two different districts of West Bengal, India. In total, three MRSE, one MRSA and three ESBL producing E. coli were isolated from these cases. Both the crossbreds were detected with MRSE (HFSE1 and HFSE2) and ESBL producing E. coli (HFEC1 and HFEC2), whereas, simultaneous infection of three pathogens viz. MRSA (NDSA1), MRSE (NDSE1) and ESBL producing E. coli (NDEC1) was found in the non-descript cow. The methicillin-resistant isolates possessed mecA gene and exhibited resistance to various antibiotics such as amikacin, tetracycline and glycopeptides. The ESBL producers were positive for blaCTX-M and blaTEM genes; in addition, HFEC1 and HFEC2 were positive for blaSHV and possessed the genes for class I integron (int1), sulphonamide resistance (sul1), quinolone resistance (qnrS) and other virulence factors (papC, iucD and ESTA1). All the ESBL producers exhibited resistance to a variety of antibiotics tested including third- and fourth-generation cephalosporins and were also intermediately resistant to carbapenems. This is the first ever report on simultaneous occurrence of MRSE, MRSA and ESBL producing E. coli in bovine mastitis indicating a major concern for dairy industry and public health as well.

  19. Shear alters motility of Escherichia coli

    Science.gov (United States)

    Molaei, Mehdi; Jalali, Maryam; Sheng, Jian

    2013-11-01

    Understanding of locomotion of microorganisms in shear flows drew a wide range of interests in microbial related topics such as biological process including pathogenic infection and biophysical interactions like biofilm formation on engineering surfaces. We employed microfluidics and digital holography microscopy to study motility of E. coli in shear flows. We controlled the shear flow in three different shear rates: 0.28 s-1, 2.8 s-1, and 28 s-1 in a straight channel with the depth of 200 μm. Magnified holograms, recorded at 15 fps with a CCD camera over more than 20 minutes, are analyzed to obtain 3D swimming trajectories and subsequently used to extract shear responses of E.coli. Thousands of 3-D bacterial trajectories are tracked. The change of bacteria swimming characteristics including swimming velocity, reorientation, and dispersion coefficient are computed directly for individual trajectory and ensemble averaged over thousands of realizations. The results show that shear suppresses the bacterial dispersions in bulk but promote dispersions near the surface contrary to those in quiescent flow condition. Ongoing analyses are focusing to quantify effect of shear rates on tumbling frequency and reorientation of cell body, and its implication in locating the hydrodynamic mechanisms for shear enhanced angular scattering. NIH, NSF, GoMRI.

  20. Pathogenic Escherichia coli and food handlers in luxury hotels in Nairobi, Kenya.

    Science.gov (United States)

    Onyango, Abel O; Kenya, Eucharia U; Mbithi, John J N; Ng'ayo, Musa O

    2009-11-01

    The epidemiology and virulence properties of pathogenic Escherichia coli among food handlers in tourist destination hotels in Kenya are largely uncharacterized. This cross-sectional study among consenting 885 food handlers working in nine luxurious tourist hotels in Nairobi, Kenya determined the epidemiology, virulence properties, antibiotics susceptibility profiles and conjugation abilities of pathogenic Escherichia coli. Pathogenic Escherichia coli was detected among 39 (4.4%) subjects, including 1.8% enteroaggregative Escherichia coli (EAEC) harboring aggR genes, 1.2% enterotoxigenic Escherichia coli (ETEC) expressing both LT and STp toxins, 1.1% enteropathogenic Escherichia coli (EPEC) and 0.2% Shiga-like Escherichia coli (EHEC) both harboring eaeA and stx2 genes respectively. All the pathotypes had increased surface hydrophobicity. Using multivariate analyses, food handlers with loose stools were more likely to be infected with pathogenic Escherichia coli. Majority 53.8% of the pathotypes were resistant to tetracycline with 40.2% being multi-drug resistant. About 85.7% pathotypes trans-conjugated with Escherichia coli K12 F(-) NA(r) LA. The carriage of multi-drug resistant, toxin expressing pathogenic Escherichia coli by this population is of public health concern because exposure to low doses can result in infection. Screening food handlers and implementing public awareness programs is recommended as an intervention to control transmission of enteric pathogens.

  1. Plasmolysis during the division cycle of Escherichia coli.

    OpenAIRE

    Olijhoek, A J; Eden, C G; Trueba, F J; Pas, E; Nanninga, N

    1982-01-01

    Cells of Escherichia coli were plasmolyzed with sucrose. They were classified according to length by way of electron micrographs taken from samples prepared by agar filtration. The percentage of plasmolyzed cells increased about two- and threefold between mean cell sizes of newborn and separating cells. However, dividing cells were less frequently plasmolyzed than nondividing cells of the same length class. Analysis of cell halves (prospective daughters) in dividing cells showed that they beh...

  2. Role for the female in bacterial conjugation in Escherichia coli.

    Science.gov (United States)

    Freifelder, D

    1967-08-01

    Hfr and F' Lac male strains of Escherichia coli were mated with purine-requiring females which had been starved for purine. These females formed mating pairs with the males. However, a mating in the absence of purine markedly reduced the yield of recombinants. Transfer of F' Lac or of lambda prophage also occurred infrequently. It was concluded that deoxyribonucleic acid transfer from male to female requires some, as yet unknown, function of the female.

  3. Maturation of the Escherichia coli divisome occurs in two steps.

    NARCIS (Netherlands)

    Aarsman, M.E.G.; Piette, A.; Fraipont, C.; Vinkenvleugel, T.M.F.; Nguyen-Distèche, M.; den Blaauwen, T.

    2005-01-01

    Cell division proteins FtsZ (FtsA, ZipA, ZapA), FtsE/X, FtsK, FtsQ, FtsL/B, FtsW, PBP3, FtsN and AmiC localize at mid cell in Escherichia coli in an interdependent order as listed. To investigate whether this reflects a time dependent maturation of the divisome, the average cell age at which FtsZ,

  4. Complementation analysis of eleven tryptophanase mutations in Escherichia coli.

    Science.gov (United States)

    White, M K; Yudkin, M D

    1979-10-01

    Nine independent mutants deficient in tryptophanase activity were isolated. Each mutation was transferred to a specialized transducing phage that carries the tryptophanase region of the Escherichia coli chromosome. The nine phages thus produced, and a tenth carrying a previously characterized tryptophanase mutation, were used to lysogenize a bacterial strain harbouring a mutation in the tryptophanase structural gene and also a suppressor of polarity. In no case was complementation observed; we conclude that there is no closely linked positive regulatory gene for tryptophanase.

  5. DNA microarray analysis of fim mutations in Escherichia coli

    DEFF Research Database (Denmark)

    Schembri, Mark; Ussery, David; Workman, Christopher

    2002-01-01

    Bacterial adhesion is often mediated by complex polymeric surface structures referred to as fimbriae. Type I fimbriae of Escherichia coli represent the archetypical and best characterised fimbrial system. These adhesive organelles mediate binding to D-mannose and are directly associated with viru...... the number of fimbriae expressed on the cell surface. The use of high-resolution oligonucleotide arrays for defining points of transcription initiation and termination is also demonstrated....

  6. Characterization of Aspergillus oryzae aspartyl aminopeptidase expressed in Escherichia coli.

    Science.gov (United States)

    Watanabe, Jun; Tanaka, Hisaki; Akagawa, Takumi; Mogi, Yoshinobu; Yamazaki, Tatsuo

    2007-10-01

    To characterize aspartyl aminopeptidase from Aspergillus oryzae, the recombinant enzyme was expressed in Escherichia coli. The enzyme cleaves N-terminal acidic amino acids. About 30% activity was retained in 20% NaCl. Digestion of defatted soybean by the enzyme resulted in an increase in the glutamic acid content, suggesting that the enzyme is potentially responsible for the release of glutamic acid in soy sauce mash.

  7. Escherichia coli and virus isolated from ''sticky kits''

    DEFF Research Database (Denmark)

    Jørgensen, M.; Scheutz, F.; Strandbygaard, Bertel

    1996-01-01

    A total of 121 Escherichia coli strains isolated from 3-week-old mink kits were serotyped and examined for virulence factors. 56 strains were isolated from healthy kits while 65 were from ''sticky kits''. Among these, 34 different serotypes were detected. No difference in serotypes or the presenc...... of virulence factors could be detected between healthy and diseased kits. By electron microscopy of faecal samples corona-, rota-, and calicivirus were demonstrated among healthy as well as diseased kits....

  8. Two Tales of Prokaryotic Genomic Diversity: Escherichia coli and Halophiles

    Directory of Open Access Journals (Sweden)

    Lejla Pašić

    2014-01-01

    Full Text Available Prokaryotes are generally characterized by vast genomic diversity that has been shaped by mutations, horizontal gene transfer, bacteriocins and phage predation. Enormous genetic diversity has developed as a result of stresses imposed in harsh environments and the ability of microorganisms to adapt. Two examples of prokaryotic diversity are presented: on intraspecies level, exemplified by Escherichia coli, and the diversity of the hypersaline environment, with the discussion of food-related health issues and biotechnological potential.

  9. Current perspectivesin pathogenesis and antimicrobial resistance of enteroaggregative Escherichia coli.

    Science.gov (United States)

    Kong, Haishen; Hong, Xiaoping; Li, Xuefen

    2015-08-01

    Enteroaggregative Escherichia coli (EAEC) is an emerging pathogen that causes acute and persistent diarrhea in children and adults. While the pathogenic mechanisms of EAEC intestinal colonization have been uncovered (including bacterial adhesion, enterotoxin and cytotoxin secretion, and stimulation of mucosal inflammation), those of severe extraintestinal infections remain largely unknown. The recent emergence of multidrug resistant EAEC represents an alarming public health threat and clinical challenge, and research on the molecular mechanisms of resistance is urgently needed.

  10. Effect of cobalt on Escherichia coli metabolism and metalloporphyrin formation

    OpenAIRE

    Majtan, Tomas; Frerman, Frank E.; Kraus, Jan P.

    2010-01-01

    Toxicity in Escherichia coli resulting from high concentrations of cobalt has been explained by competition of cobalt with iron in various metabolic processes including Fe–S cluster assembly, sulfur assimilation, production of free radicals and reduction of free thiol pool. Here we present another aspect of increased cobalt concentrations in the culture medium resulting in the production of cobalt protoporphyrin IX (CoPPIX), which was incorporated into heme proteins including membrane-bound c...

  11. Maturation of the Escherichia coli divisome occurs in two steps.

    NARCIS (Netherlands)

    Aarsman, M.E.G.; Piette, A.; Fraipont, C.; Vinkenvleugel, T.M.F.; Nguyen-Distèche, M.; den Blaauwen, T.

    2005-01-01

    Cell division proteins FtsZ (FtsA, ZipA, ZapA), FtsE/X, FtsK, FtsQ, FtsL/B, FtsW, PBP3, FtsN and AmiC localize at mid cell in Escherichia coli in an interdependent order as listed. To investigate whether this reflects a time dependent maturation of the divisome, the average cell age at which FtsZ, F

  12. Multiple defects in Escherichia coli mutants lacking HU protein.

    OpenAIRE

    Huisman, O; Faelen, M; Girard, D; Jaffé, A; Toussaint, A; Rouvière-Yaniv, J

    1989-01-01

    The HU protein isolated from Escherichia coli, composed of two partially homologous subunits, alpha and beta, shares some of the properties of eucaryotic histones and is a major constituent of the bacterial nucleoid. We report here the construction of double mutants totally lacking both subunits of HU protein. These mutants exhibited poor growth and a perturbation of cell division, resulting in the formation of anucleate cells. In the absence of HU, phage Mu was unable to grow, to lysogenize,...

  13. PROFILE OF RESISTANCE OF Escherichia coli ISOLATED FROM CANINE PYOMETRA

    Directory of Open Access Journals (Sweden)

    Fernanda Santana Oliveira

    2016-10-01

    Full Text Available The endothelial pyometra is a disease that affects more frequently reproductively active adult females. Characterized by inflammation and accumulation of exudate in the uterine cavity, generally associated with bacterial infections. The present study aimed to evaluate the resistance profile of Escherichia coli isolates from 42 female dogs diagnosed with pyometra, seen at the Department of Small Animal Surgery, Hospital of Veterinary Medicine, Federal University of Bahia. To perform the bacteriological analysis, a sample of the contents of the uterus was obtained immediately after surgery of ovariosalpingohisterectomy therapy (OSH and sent to the laboratory. Microbiological analysis showed a predominance of the bacterium Escherichia coli in 40.5% (15/37. Strains of Escherichia coli isolates showed higher rates of resistance to antimicrobial erythromycin (93.3 %, azithromycin (80 %, ampicillin, amoxicillin, and cephalothin (40% each. This study reinforces the need to perform the microbiological examination for epidemiological purposes and the correct therapeutic application, thereby avoiding the indiscriminate use of antimicrobials and the potential emergence of multidrug-resistant  strains. Keywords: bacteria; multiresistant;  uterus.

  14. Vaginal Escherichia coli share common virulence factor profiles, serotypes and phylogeny with other extraintestinal E. coli

    National Research Council Canada - National Science Library

    Obata-Yasuoka, Mana; Ba-Thein, William; Tsukamoto, Teizo; Yoshikawa, Hiroyuki; Hayashi, Hideo

    2002-01-01

    ...: William Ba-Thein. Tel: +81 298 53 3354. Fax: +81 298 53 3354. e-mail: bathein{at}md.tsukuba.ac.jp Characteristics of Escherichia coli residing in the vagina and their role in extraintestinal infections are largely unknown...

  15. The asymptomatic bacteriuria Escherichia coli strain 83972 outcompetes uropathogenic E. coli strains in human urine

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Ulett, G.C.; Schembri, M.A.

    2006-01-01

    Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic urinary tract infections (UTI), very little is known about the mechanisms by which these strains colonize the human urinary tract....... The prototype ABU E. coli strain 83972 was originally isolated from a girl who had carried it asymptomatically for 3 years. Deliberate colonization of UTI-susceptible individuals with E. coli 83972 has been used successfully as an alternative approach for the treatment of patients who are refractory...... to conventional therapy. Colonization with strain 83972 appears to prevent infection with UPEC strains in such patients despite the fact that this strain is unable to express the primary adhesins involved in UTI, viz. P and type 1 fimbriae. Here we investigated the growth characteristics of E. coli 83972 in human...

  16. Prevalence of Escherichia coli in apple cider manufactured in Connecticut.

    Science.gov (United States)

    Dingman, D W

    1999-06-01

    Cider samples obtained from 11 cider mills operating in Connecticut during the 1997 to 1998 production season were tested for the presence of Escherichia coli. Cider production began in mid August and continued through March, with peak production in September and October. Of 314 cider samples tested, 11 (4%) were found to contain E. coli. Of the 11 mills, 6 (55%) tested positive for E. coli in the cider at least once during the production year. E. coli was first observed in cider samples produced in mid to late October and was not detected in samples made after January. A trend was observed for cider to decrease in acidity and increase in Brix (soluble sugars) throughout the production season. No correlation between pH and soluble sugars of cider and the presence of E. coli was detected. Eight mills used both dropped apples and tree-picked apples, whereas three mills used tree-picked apples only. The use of dropped apples in cider production began 5 weeks before the first detection of E. coli in cider. E. coli was isolated from cider samples produced using dropped apples and from samples produced using only tree-picked apples. No direct correlation between the use of dropped apples or tree-picked apples and the presence of E. coli in the cider was observed. An association between the time of apple harvest and the appearance of E. coli in cider was noted. For mills providing adequate records, all contaminated cider was produced from apples harvested between mid October and mid November.

  17. Dynamics of chromosome segregation in Escherichia coli

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck

    2007-01-01

    in the cell by labeling specific parts of it. Later the dynamics of chromosome segregation was included. Investigating chromosome organization by labeling of specific loci was already a widely used technique when I started on this thesis, but the data acquisition and treatment was slow and generally poorly......, and it is obvious that structured cellular actions are required to unpack it, as required for its replication, and refold the two daughter chromosomes separately without getting them entangled in the process each generation. The intention of the study was initially to find out how the chromosome is organized....... Adding the results of the thesis together with known data results in the following description of the chromosome dynamics of slowly growing E.coli cells: The chromosome of slow growing cells is organized with the origin at the cell center when it is newborn. It has one chromosomal arm on one side...

  18. Prevalence of quinolone resistance determinants in non-typhoidal Salmonella isolates from human origin in Extremadura, Spain.

    Science.gov (United States)

    Campos, Maria Jorge; Palomo, Gonzalo; Hormeño, Lorena; Herrera-León, Silvia; Domínguez, Lucas; Vadillo, Santiago; Píriz, Segundo; Quesada, Alberto

    2014-05-01

    Resistance to the quinolones nalidixic acid (NAL) and ciprofloxacin (CIP) and the occurrence of quinolone resistance determinants have been investigated in 300 non-typhoidal Salmonella from human origin, isolated in the years between 2004 and 2008, in 6 hospitals within Extremadura (Spain). Salmonella Enteritidis was the major serotype found among quinolone-resistant isolates, most of which were clustered by clonal analysis to a single clone, which presented D87 or S83 substitutions in GyrA. Eleven isolates presented the non-classical quinolone resistance phenotype (resistance to CIP and susceptibility to NAL), lacking mutations in the quinolone resistance determinant region of topoisomerase genes. Among them, one Salmonella Typhimurium isolate carried a qnrS1 gene in a low-molecular-weight plasmid, pQnrS1-HLR25, identical to plasmids previously found in the UK, Taiwan, and USA. The occurrence of this genetic element could represent a risk for the horizontal transmission of quinolone resistance among Enterobacteriaceae in the Iberian Peninsula.

  19. Prevalence of plasmid-mediated AmpC β-lactamase-producing Escherichia coli and spread of the ST131 clone among extended-spectrum β-lactamase-producing E. coli in Japan.

    Science.gov (United States)

    Matsumura, Yasufumi; Yamamoto, Masaki; Higuchi, Takeshi; Komori, Toshiaki; Tsuboi, Fusayuki; Hayashi, Akihiko; Sugimoto, Yoshihisa; Hotta, Gou; Matsushima, Aki; Nagao, Miki; Takakura, Shunji; Ichiyama, Satoshi

    2012-08-01

    In 2010, a total of 1327 clinical Escherichia coli isolates from five hospitals in the Kyoto and Shiga regions of Japan were analysed by PCR. The prevalences of plasmid-mediated AmpC β-lactamase (pAmpC)-producers, extended-spectrum β-lactamase (ESBL)-producers and co-producers of pAmpC and ESBL were 1.7%, 9.7% and 0.3%, respectively. Less than one-half of the pAmpC-producers were reported to be resistant to third-generation cephalosporins, cephamycins and β-lactam/β-lactam inhibitors using the old 2009 Clinical and Laboratory Standards Institute (CLSI) breakpoints. CMY-2 was the most prevalent pAmpC type (95%), and CTX-M-14 (38%), CTX-M-15 (26%) and CTX-M-27 (19%) were the most prevalent ESBL types. The worldwide O25b-ST131-B2 clone accounted for 11% of pAmpC-producers and 41% of ESBL-producers. The O25b-ST131-B2 clone was characterised by a CTX-M-27- or CTX-M-15-type ESBL and ciprofloxacin-non-susceptibility with quadruple mutations in the quinolone resistance-determining regions (S83L and D87N in GyrA and S80I and E84V in ParC). A significant proportion of pAmpC-producers and the O25b-ST131-B2 clone were found in Japan by a recent regional surveillance programme.

  20. Measuring Escherichia coli Gene Expression during Human Urinary Tract Infections

    Science.gov (United States)

    Mobley, Harry L. T.

    2016-01-01

    Extraintestinal Escherichia coli (E. coli) evolved by acquisition of pathogenicity islands, phage, plasmids, and DNA segments by horizontal gene transfer. Strains are heterogeneous but virulent uropathogenic isolates more often have specific fimbriae, toxins, and iron receptors than commensal strains. One may ask whether it is the virulence factors alone that are required to establish infection. While these virulence factors clearly contribute strongly to pathogenesis, bacteria must survive by metabolizing nutrients available to them. By constructing mutants in all major metabolic pathways and co-challenging mice transurethrally with each mutant and the wild type strain, we identified which major metabolic pathways are required to infect the urinary tract. We must also ask what else is E. coli doing in vivo? To answer this question, we examined the transcriptome of E. coli CFT073 in the murine model of urinary tract infection (UTI) as well as for E. coli strains collected and analyzed directly from the urine of patients attending either a urology clinic or a university health clinic for symptoms of UTI. Using microarrays and RNA-seq, we measured in vivo gene expression for these uropathogenic E. coli strains, identifying genes upregulated during murine and human UTI. Our findings allow us to propose a new definition of bacterial virulence. PMID:26784237

  1. Fluorogenic assay for rapid detection of Escherichia coli in food.

    Science.gov (United States)

    Moberg, L J

    1985-12-01

    An assay procedure to screen for Escherichia coli in foods by using 4-methylumbelliferyl-beta-D-glucuronide (MUG) incorporated into lauryl tryptose (LST) broth was evaluated. The beta-glucuronidase produced by E. coli cleaves the MUG substrate to yield a fluorescent end product. E. coli-negative samples can be identified by lack of fluorescence in LST-MUG within 24 h. MUG was not inhibitory to coliforms and E. coli. Over 1,400 food and dairy samples were tested to compare the standard three-tube most-probable-number procedure with the MUG-containing or non-MUG-containing LST procedure. LST-MUG testing detected a greater number of E. coli, with a lower false-positive rate (1.4%) and in a shorter time, than did the standard procedure. All false-positive results in the LST-MUG testing were attributable to beta-glucuronidase-producing staphylococci. No false-negative result was encountered. Use of MUG in LST broth obviates the EC broth step, allowing a 2.5-day procedure to a completed E. coli test versus the present 4- to 6-day standard most-probable-number method.

  2. Examination of uropathogenic Escherichia coli strains conferring large plasmids

    Directory of Open Access Journals (Sweden)

    SUHARTONO

    2010-04-01

    Full Text Available Suhartono (2010 Examination of uropathogenic Escherichia coli strains conferring large plasmids. Biodiversitas 11: 59-64. Of major uropathogens, Escherichia coli has been widely known as a main pathogen of UTIs globally and has considerable medical and financial consequences. A strain of UPEC, namely E. coli ST131, confers a large plasmid encoding cephalosporinases (class C β-lactamase or AmpC that may be disseminated through horizontal transfer among bacterial populations. Therefore, it is worth examining such large plasmids by isolating, purifying, and digesting the plasmid with restriction enzymes. The examination of the large plasmids was conducted by isolating plasmid DNA visualized by agarose gel electrophoresis as well as by PFGE. The relationship of plasmids among isolates was carried out by HpaI restriction enzyme digestion. Of 36 isolates of E. coli ST 131, eight isolates possessed large plasmids, namely isolates 3, 9, 10, 12, 17, 18, 26 and 30 with the largest molecular size confirmed by agarose gel electrophoresis and PFGE was ~42kb and ~118kb respectively. Restriction enzyme analysis revealed that isolates 9, 10, 12, 17 and 18 have the common restriction patterns and those isolates might be closely related.

  3. Characterization of KPC-2-producing Escherichia coli, Citrobacter freundii, Enterobacter cloacae, Enterobacter aerogenes, and Klebsiella oxytoca isolates from a Chinese Hospital.

    Science.gov (United States)

    Luo, Yanping; Yang, Jiyong; Ye, Liyan; Guo, Lin; Zhao, Qiang; Chen, Rong; Chen, Yong; Han, Xuelin; Zhao, Jingya; Tian, Shuguang; Han, Li

    2014-08-01

    Twelve nonduplicated KPC-2-producing enterobacterial isolates, including three Escherichia coli, two Citrobacter freundii, two Enterobacter cloacae, four Enterobacter aerogenes, and one Klebsiella oxytoca, were collected from various clinical samples within 18 months (March 2011 to September 2012). Two of the 12 patients died from infections caused by KPC-2-producing pathogens, while the rest of the patients with KPC-2-producing pathogens improved or were cured. The majority of the clinical isolates exhibited a high-level of resistance to oxyimino-cephalosporins and carbapenems, and possessed self-transferable bla(KPC-2)-carrying plasmids with sizes ranging from 20 to 120 kb. Most isolates carried bla(CTX-M) and plasmid-mediated quinolone resistance genes, while some isolates produced 16S rRNA methylases (ArmA or RmtB). The genetic environment of bla(KPC-2) of most clinical strains was consistent with the genetic structure surrounding bla(KPC-2) on the plasmid pKP048, which contains an integration structure of a Tn3-based transposon and partial Tn4401 segment. Inserted fragments (truncated bla(TEM)) were detected upstream of the bla(KPC-2) gene for two E. aerogenes strains. In conclusion, the enterobacterial isolates exhibited sporadic emergence and did not arise by clonal spread at our hospital. The outcome of infections caused by KPC-producing enterobacterial isolates and their mortality were closely associated with the baseline condition of patients. The spread of bla(KPC-2) gene between different enterobacterial species in China was mainly mediated by horizontal transfer of the Tn3-based transposons and not the bla(KPC-2)-carrying plasmids.

  4. Production of isopropanol by metabolically engineered Escherichia coli.

    Science.gov (United States)

    Jojima, Toru; Inui, Masayuki; Yukawa, Hideaki

    2008-01-01

    A genetically engineered strain of Escherichia coli JM109 harboring the isopropanol-producing pathway consisting of five genes encoding four enzymes, thiolase, coenzyme A (CoA) transferase, acetoacetate decarboxylase from Clostridium acetobutylicum ATCC 824, and primary-secondary alcohol dehydrogenase from C. beijerinckii NRRL B593, produced up to 227 mM of isopropanol from glucose under aerobic fed-batch culture conditions. Acetate production by the engineered strain was approximately one sixth that produced by a control E. coli strain bearing an expression vector without the clostridial genes. These results demonstrate a functional isopropanol-producing pathway in E. coli and consequently carbon flux from acetyl-CoA directed to isopropanol instead of acetate. This is the first report on isopropanol production by genetically engineered microorganism under aerobic culture conditions.

  5. Protein abundance profiling of the Escherichia coli cytosol

    DEFF Research Database (Denmark)

    Ishihama, Y.; Schmidt, T.; Rappsilber, J.

    2008-01-01

    PAI approach which takes into account the number of sequenced peptides per protein. The values of abundance are within a broad range and accurately reflect independently measured copy numbers per cell. As expected, the most abundant proteins were those involved in protein synthesis, most notably ribosomal...... sample. Using a combination of LC-MS/MS approaches with protein and peptide fractionation steps we identified 1103 proteins from the cytosolic fraction of the Escherichia coli strain MC4100. A measure of abundance is presented for each of the identified proteins, based on the recently developed em...... protein and mRNA abundance in E. coli cells. Conclusion: Abundance measurements for more than 1000 E. coli proteins presented in this work represent the most complete study of protein abundance in a bacterial cell so far. We show significant associations between the abundance of a protein and its...

  6. The Escherichia coli transcriptome linked to growth fitness

    Directory of Open Access Journals (Sweden)

    Bei-Wen Ying

    2016-03-01

    Full Text Available A series of Escherichia coli strains with varied genomic sequences were subjected to high-density microarray analyses to elucidate the fitness-correlated transcriptomes. Fitness, which is commonly evaluated by the growth rate during the exponential phase, is not only determined by the genome but is also linked to growth conditions, e.g., temperature. We previously reported genetic and environmental contributions to E. coli transcriptomes and evolutionary transcriptome changes in thermal adaptation. Here, we describe experimental details on how to prepare microarray samples that truly represent the growth fitness of the E. coli cells. A step-by-step record of sample preparation procedures that correspond to growing cells and transcriptome data sets that are deposited at the GEO database (GSE33212, GSE52770, GSE61739 are also provided for reference.

  7. Pulsed ultra-violet inactivation spectrum of Escherichia coli.

    Science.gov (United States)

    Wang, T; Macgregor, S J; Anderson, J G; Woolsey, G A

    2005-08-01

    Inactivation of Escherichia coli is examined using ultra-violet (UV) radiation from a pulsed xenon flashlamp. The light from the discharge has a broadband emission spectrum extending from the UV to the infrared region with a rich UV content. The flashlamp provides high-energy UV output using a small number of short-duration pulses (30 micros). The flashlamp is used with a monochromator to investigate the wavelength sensitivity of E. coli to inactivation by the pulsed UV light. Using 8 nm wide pulses of UV radiation, the most efficient inactivation is found to occur at around 270 nm and no inactivation is observed above 300 nm. A pyroelectric detector allows the energy dose to be determined at each wavelength, and a peak value for E. coli population reduction of 0.43 log per mJ/cm(2) is measured at 270 nm. The results are compared with the published data available for continuous UV light sources.

  8. Escherichia coli portador de betalactamasas de espectro extendido: resistencia

    Directory of Open Access Journals (Sweden)

    Mª C. Miranda García

    2013-12-01

    Full Text Available Introducción: Escherichia coli es el microorganismo que con más frecuencia se encuentra implicado en infecciones nosocomiales y comunitarias, patógeno responsable en la etiología de infecciones de vías respiratorias altas, infecciones del tracto urinario, heridas quirúrgicas, sangre o gastroenteritis. En los últimos años ha experimentado importantes cambios encontrándose un aumento de infecciones por cepas de éstos microorganismos productores de betalactamasas de espectro extendido. Objetivos: Se decide hacer este estudio retrospectivo de las muestras procesadas en el Laboratorio de Microbiología del Hospital Básico de la Defensa San Carlos (San Fernando, para conocer la frecuencia y el patrón de sensibilidad en nuestra población por gérmenes productores de betalactamasas de espectro extendido en este caso por Escherichia coli, dada la importancia de las infecciones causadas por esta bacteria y la repercusión que tiene por todo el mundo los mecanismos de resistencia. Material y Método: Se recogieron los datos de resultados obtenidos en las muestras procesadas en el Laboratorio de Microbiología durante 36 meses (Enero 2009 a Diciembre 2011, en las que se hubieran identificado cepas de Escherichia coli y de éstas las productoras de betalactamasas de espectro extendido. Resultados: Se aislaron 34 cepas de Escherichia coli productoras de betalactamasas de espectro extendido lo que supone una tasa del 5,10%. Se encontró una frecuencia mayor en el año 2010 (6,9% que en el 2009 (2,61%, pero similar al 2011 (5,98%. Conclusión: La frecuencia de cepas Escherichia coli con betalactamasas de espectro extendido encontrada es similar a la de otros estudios realizados en España, pero la tasa de resistencia de algunos antimicrobianos como Amoxicilina/clavulánico, Cotrimoxazol y Fluorquinolonas en nuestra población es elevada.

  9. Quinolone Resistance among Salmonella enterica from Cattle, Broilers and Swine in Denmark

    DEFF Research Database (Denmark)

    Wiuff, C.; Baggesen, Dorte Lau; Madsen, M.

    2000-01-01

    This study was conducted to determine the susceptibility to nalidixic acid and fluoroquinolones of Salmonella Dublin, S. Enteritidis, and S. Typhimurium isolates from cattle, broilers, and pigs over time in Denmark and to characterise the gyrA, gyrB, and parC genes in quinolone-resistant isolates......, and one from 1999 were resistant to nalidixic acid. All the nalidixic acid-resistant isolates had reduced susceptibility to fluoroquinolones. Sequence analysis of the gyrA gene in 37 nalidixic-resistant isolates identified two different base substitutions at codon serine-83 and two at aspartate-87...

  10. Protective effects of indigenous Escherichia coli against a pathogenic E. coli challenge strain in pigs.

    Science.gov (United States)

    Vahjen, W; Cuisiniere, T; Zentek, J

    2017-10-03

    To investigate the inhibitory effect of indigenous enterobacteria on pathogenic Escherichia coli, a challenge trial with postweaning pigs was conducted. A pathogenic E. coli strain was administered to all animals and their health was closely monitored thereafter. Faecal samples were taken from three healthy and three diarrhoeic animals. Samples were cultivated on MacConkey agar and isolates were subcultured. A soft agar overlay assay was used to determine the inhibitory activity of the isolates. A total of 1,173 enterobacterial isolates were screened for their ability to inhibit the E. coli challenge strain. Colony forming units of enterobacteria on MacConkey agar were not different between healthy and diarrhoeic animals in the original samples. Furthermore, numbers of isolates per animal were also not significantly different between healthy (482 isolates) and diarrhoeic animals (691 isolates). A total of 43 isolates (3.7%) with inhibitory activity against the pathogenic E. coli challenge strain were detected. All inhibitory isolates were identified as E. coli via MALDI-TOF. The isolates belonged to the phylotypes A, C and E. Many isolates (67.4%) were commensal E. coli without relevant porcine pathogenic factors, but toxin- and fimbrial genes (stx2e, fae, estIb, elt1a, fas, fan) were detected in 14 inhibitory isolates. Healthy animals showed significantly (P=0.003) more inhibitory isolates (36 of 482 isolates; 7.5%) than diseased animals (7 of 691 isolates; 1.0%). There were no significant correlations regarding phylotype or pathogenic factors between healthy and diseased animals. This study has shown that a small proportion of indigenous E. coli is able to inhibit in vitro growth of a pathogenic E. coli strain in pigs. Furthermore, healthy animals possess significantly more inhibitory E. coli strains than diarrhoeic animals. The inhibition of pathogenic E. coli by specific indigenous E. coli strains may be an underlying principle for the containment of pathogenic

  11. Evaluation of Five Jet Fuels in the Salmonella-Escherichia coli / Microsome Plate Incorporation Assay

    Science.gov (United States)

    2010-09-01

    AFRL-RH-WP-TR-2010-0138 Evaluation of Five Jet Fuels in the Salmonella-Escherichia coli / Microsome Plate Incorporation Assay Edward S...31 Jul 2010 4. TITLE AND SUBTITLE Evaluation of Five Jet Fuels in the Salmonella-Escherichia coli / Microsome Plate Incorporation Assay 5a...the Salmonella typhimurium-Escherichia coli/ microsome plate incorporation assay. The assay was performed using the plate incorporation procedure

  12. Attachment of Escherichia coli and enterococci to particles in runoff.

    Science.gov (United States)

    Soupir, Michelle L; Mostaghimi, Saied; Dillaha, Theo

    2010-01-01

    Association of Escherichia coli and enterococci with particulates present in runoff from erodible soils has important implications for modeling the fate and transport of bacteria from agricultural sources and in the selection of management practices to reduce bacterial movement to surface waters. Three soils with different textures were collected from the Ap horizon (silty loam, silty clay loam, and loamy fine sand), placed in portable box plots, treated with standard cowpats, and placed under a rainfall simulator. Rainfall was applied to the plots until saturation-excess flow occurred for 30 min, and samples were collected 10, 20, and 30 min after initiation of the runoff event. The attachment of E. coli and enterococci to particles present in runoff was determined by a screen filtration and centrifugation procedure. Percentage of E. coli and enterococci attached to particulates in runoff ranged from 28 to 49%, with few statistically significant differences in attachment among the three soils. Similar partitioning release patterns were observed between E. coli and enterococci from the silty loam (r = 0.57) and silty clay loam soils (r = 0.60). At least 60% of all attached E. coli and enterococci were associated particles within an 8- to 62-microm particle size category. The results indicate that the majority of fecal bacteria attach to and are transported with manure colloids in sediment-laden flow regardless of the soil texture.

  13. Multiple antimicrobial resistance among Avian Escherichia coli strains in Albania

    Directory of Open Access Journals (Sweden)

    Antonio Camarda

    2010-01-01

    Full Text Available In this study, 101 Escherichia (E. coli isolates from broilers, laying hens and turkeys which had died from colibacillosis, collected from 37 intensive and rural farms in Albania, were tested for antimicrobial susceptibility toward 12 different molecules. The highest levels of resistance were observed for Erythromycin (E (100% Amoxicillin (AMX (99.1%, Tetracycline (TE 30 (96.07%, Streptomycin (STR (93.07% and Neomycin (N30 (85.15%. Considerable resistance was also detected for fluoroquinolones. Moreover, 73.33% of E. coli resistant to at least one fluoroquinolone were also resistant to the two other fluoroquinolones checked. No evident differences were found between the E. coli from intensive and from rural farms. Multiple antibiotic resistance was expressed by all the E. coli tested. 23.63% and 17.39% of E. coli isolated from intensive and rural farms, respectively, were resistant towards all the drugs tested. These data would seem to indicate incorrect use of antibiotics on poultry farms in Albania.

  14. Escherichia coli exports cyclic AMP via TolC.

    Science.gov (United States)

    Hantke, Klaus; Winkler, Karin; Schultz, Joachim E

    2011-03-01

    In Escherichia coli more than 180 genes are regulated by the cyclic AMP (cAMP)-cAMP receptor protein (CRP) complex. However, more than 90% of cAMP that is made by intracellular adenylyl cyclases is found in the culture medium. How is cAMP exported from E. coli? In a tolC mutant, 0.03 mM IPTG (isopropyl-β-d-thiogalactopyranoside) was sufficient to induce β-galactosidase compared to 0.1 mM IPTG in the parent strain. In a cya mutant unable to produce cAMP about 1 mM extracellular cAMP was required to induce β-galactosidase, whereas in a cya tolC mutant 0.1 mM cAMP was sufficient. When cAMP in E. coli cya was generated intracellularly by a recombinant, weakly active adenylyl cyclase from Corynebacterium glutamicum, the critical level of cAMP necessary for induction of maltose degradation was only achieved in a tolC mutant and not in the parent strain. Deletion of a putative cAMP phosphodiesterase of E. coli, CpdA, resulted in a slightly similar, yet more diffuse phenotype. The data demonstrate that export of cAMP via TolC is a most efficient way of E. coli to lower high concentrations of cAMP in the cell and maintain its sensitivity in changing metabolic environments.

  15. Phylogenetic analysis of Escherichia coli strains isolated from human samples

    Directory of Open Access Journals (Sweden)

    Abdollah Derakhshandeh

    2013-12-01

    Full Text Available Escherichia coli (E. coli is a normal inhabitant of the gastrointestinal tract of vertebrates, including humans. Phylogenetic analysis has shown that E. coli is composed of four main phylogenetic groups (A, B1, B2 and D. Group A and B1 are generally associated with commensals, whereas group B2 is associated with extra-intestinal pathotypes. Most enteropathogenic isolates, however, are assigned to group D. In the present study, a total of 102 E. coli strains, isolated from human samples, were used. Phylogenetic grouping was done based on the Clermont triplex PCR method using primers targeted at three genetic markers, chuA, yjaA and TspE4.C2. Group A contained the majority of the collected isolates (69 isolates, 67.64%, followed by group B2 (18 isolates, 17.64% and D (15 isolates, 14.7% and no strains were found to belong to group B1. The distribution of phylogenetic groups in our study suggests that although the majority of strains were commensals, the prevalence of enteropathogenic and extra-intestinal pathotypes was noteworthy. Therefore, the role of E. coli in human infections including diarrhea, urinary tract infections and meningitis should be considered.

  16. Role of peripheral pooling in porcine Escherichia coli sepsis

    Energy Technology Data Exchange (ETDEWEB)

    Teule, G.J.; von Lingen, A.; Verwey von Vught, M.A.; Kester, A.D.; Mackaay, R.C.; Bezemer, P.D.; Heidenal, G.A.; Thijs, L.G.

    1984-01-01

    In anesthesized pigs the effects of E. coli (2 X 10(8)/kg) on hemodynamics and red cell distribution were studied. After injection of 99m-Tc red cells (15 mCi), regional radioactivity was followed during 3 hours. Gated bloodpool studies were performed to measure end-diastolic volumes (EDV). Escherichia coli E. coli was infused in 14 pigs, while 7 animals served as controls. E. coli resulted in an early increase in pulmonary arterial pressure. Systemic arterial pressure decreased gradually, while cardiac output did not change significantly. The gated studies revealed that especially left ventricular end-diastolic volume (LVEDV) declined, to 50% of the basal value. Regional radioactivity did not change over lungs, liver and abdomen. Splenic activity declined markedly. Over the hindlimb a significant increase (29 +/- 8%) was observed. It is concluded that E. coli infusion in pigs induces a hemodynamic pattern similar to human sepsis. The decrease in LVEDV is probably related to peripheral pooling and a change in right ventricle (RV) performance.

  17. The genetic basis of Escherichia coli pathoadaptation to macrophages.

    Directory of Open Access Journals (Sweden)

    Migla Miskinyte

    Full Text Available Antagonistic interactions are likely important driving forces of the evolutionary process underlying bacterial genome complexity and diversity. We hypothesized that the ability of evolved bacteria to escape specific components of host innate immunity, such as phagocytosis and killing by macrophages (MΦ, is a critical trait relevant in the acquisition of bacterial virulence. Here, we used a combination of experimental evolution, phenotypic characterization, genome sequencing and mathematical modeling to address how fast, and through how many adaptive steps, a commensal Escherichia coli (E. coli acquire this virulence trait. We show that when maintained in vitro under the selective pressure of host MΦ commensal E. coli can evolve, in less than 500 generations, virulent clones that escape phagocytosis and MΦ killing in vitro, while increasing their pathogenicity in vivo, as assessed in mice. This pathoadaptive process is driven by a mechanism involving the insertion of a single transposable element into the promoter region of the E. coli yrfF gene. Moreover, transposition of the IS186 element into the promoter of Lon gene, encoding an ATP-dependent serine protease, is likely to accelerate this pathoadaptive process. Competition between clones carrying distinct beneficial mutations dominates the dynamics of the pathoadaptive process, as suggested from a mathematical model, which reproduces the observed experimental dynamics of E. coli evolution towards virulence. In conclusion, we reveal a molecular mechanism explaining how a specific component of host innate immunity can modulate microbial evolution towards pathogenicity.

  18. Unusual "flesh-eating" strains of Escherichia coli.

    Science.gov (United States)

    Shaked, Hila; Samra, Zmira; Paul, Michal; Madar-Shapiro, Liora; Cohen, Jonathan; Pitlik, Silvio; Bishara, Jihad

    2012-12-01

    Monomicrobial necrotizing fasciitis (type II) is typically caused by group A streptococcus alone or in combination with Staphylococcus aureus. Escherichia coli has been isolated from polymicrobial or Fournier's gangrene but has rarely been reported in monomicrobial necrotizing fasciitis. We describe the clinical characteristics and outcomes of seven cases of monomicrobial E. coli necrotizing fasciitis and/or severe soft tissue infection diagnosed at a single institution during an 18-month period. Four isolates from three patients and two isolates from two patients with type I polymicrobial severe soft tissue infection (controls) were assayed by the randomly amplified polymorphic DNA (RAPD) analysis for fingerprinting and PCR amplification of primers in order to detect cytotoxic necrotizing factor 1 and 2 (cnf1 and cnf2) genes. All patients had some type of immune suppression. The limb was the most commonly involved organ. In all cases, E. coli was isolated as a monomicrobial pathogen from blood, fascia, or both. All patients died during hospitalization, three within the first 48 h. The RAPD amplification assay showed a high degree of genetic diversity among the "flesh-eating" strains and controls. The cnf1 toxin gene was identified in two out of three cases, but not in the controls. cnf2 was not detected in any of the patients. E. coli may be responsible for life-threatening necrotizing fasciitis. Further research is needed to reveal relevant risk factors, reservoirs, and modes of transmission of cnf1 E. coli.

  19. Escherichia coli ST131, an Intriguing Clonal Group

    Science.gov (United States)

    Bertrand, Xavier; Madec, Jean-Yves

    2014-01-01

    SUMMARY In 2008, a previously unknown Escherichia coli clonal group, sequence type 131 (ST131), was identified on three continents. Today, ST131 is the predominant E. coli lineage among extraintestinal pathogenic E. coli (ExPEC) isolates worldwide. Retrospective studies have suggested that it may originally have risen to prominence as early as 2003. Unlike other classical group B2 ExPEC isolates, ST131 isolates are commonly reported to produce extended-spectrum β-lactamases, such as CTX-M-15, and almost all are resistant to fluoroquinolones. Moreover, ST131 E. coli isolates are considered to be truly pathogenic, due to the spectrum of infections they cause in both community and hospital settings and the large number of virulence-associated genes they contain. ST131 isolates therefore seem to contradict the widely held view that high levels of antimicrobial resistance are necessarily associated with a fitness cost leading to a decrease in pathogenesis. Six years after the first description of E. coli ST131, this review outlines the principal traits of ST131 clonal group isolates, based on the growing body of published data, and highlights what is currently known and what we need to find out to provide public health authorities with better information to help combat ST131. PMID:24982321

  20. Nonthermal atmospheric argon plasma jet effects on Escherichia coli biomacromolecules.

    Science.gov (United States)

    Hosseinzadeh Colagar, Abasalt; Memariani, Hamed; Sohbatzadeh, Farshad; Valinataj Omran, Azadeh

    2013-12-01

    Nonthermal atmospheric plasma jet, a promising technology based on ionized gas at low temperatures, can be applied for disinfection of contaminated surfaces. In this study, Escherichia coli cells and their macromolecules were exposed to the nonthermal atmospheric argon plasma jet for different time durations. Total protein, genomic DNA, and malondialdehyde (MDA) levels of E. coli were assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining; agarose gel electrophoresis; and measurement of absorbance at 534 nm, respectively. After exposure, the spectroscopic results of liquid samples indicated that the survival reduction of E. coli can reach to 100 % in an exposure time of 600 s. Moreover, inactivation zones of E. coli, DNA degradation, and MDA levels were significantly increased. Additionally, banding patterns of total protein were changed and amino acid concentrations increased following ninhydrin test. The experimental results suggest that the nonthermal plasma could serve as an effective instrument for both sterilizing E. coli and degrading macromolecules from the surface of the objects being sterilized.

  1. Paper-based ELISA to rapidly detect Escherichia coli.

    Science.gov (United States)

    Shih, Cheng-Min; Chang, Chia-Ling; Hsu, Min-Yen; Lin, Jyun-Yu; Kuan, Chen-Meng; Wang, Hsi-Kai; Huang, Chun-Te; Chung, Mu-Chi; Huang, Kui-Chou; Hsu, Cheng-En; Wang, Chun-Yuan; Shen, Ying-Cheng; Cheng, Chao-Min

    2015-12-01

    Escherichia coli is a generic indicator of fecal contamination, and certain serotypes cause food- and water-borne illness such as O157:H7. In the clinic, detection of bacteriuria, which is often due to E. coli, is critical before certain surgical procedures or in cases of nosocomial infection to prevent further adverse events such as postoperative infection or sepsis. In low- and middle-income countries, where insufficient equipment and facilities preclude modern methods of detection, a simple, low-cost diagnostic device to detect E. coli in water and in the clinic will have significant impact. We have developed a simple paper-based colorimetric platform to detect E. coli contamination in 5h. On this platform, the mean color intensity for samples with 10(5)cells/mL is 0.118±0.002 (n=4), and 0.0145±0.003 (Ppaper-based ELISA is an innovative point-of-care diagnostic tool to rapidly detect E. coli, and possibly other pathogens when customized as appropriate, especially in areas that lack advanced clinical equipment.

  2. Pulsed-Plasma Disinfection of Water Containing Escherichia coli

    Science.gov (United States)

    Satoh, Kohki; MacGregor, Scott J.; Anderson, John G.; Woolsey, Gerry A.; Fouracre, R. Anthony

    2007-03-01

    The disinfection of water containing the microorganism, Escherichia coli (E. coli) by exposure to a pulsed-discharge plasma generated above the water using a multineedle electrode (plasma-exposure treatment), and by sparging the off-gas of the pulsed plasma into the water (off-gas-sparging treatment), is performed in the ambient gases of air, oxygen, and nitrogen. For the off-gas-sparging treatment, bactericidal action is observed only when oxygen is used as the ambient gas, and ozone is found to generate the bactericidal action. For the plasma-exposure treatment, the density of E. coli bacteria decreases exponentially with plasma-exposure time for all the ambient gases. It may be concluded that the main contributors to E. coli inactivation are particle species produced by the pulsed plasma. For the ambient gases of air and nitrogen, the influence of acidification of the water in the system, as a result of pulsed-plasma exposure, may also contribute to the decay of E. coli density.

  3. Prevalence and characteristics of extended-spectrum β-lactamase and plasmid-mediated fluoroquinolone resistance genes in Escherichia coli isolated from chickens in Anhui province, China.

    Directory of Open Access Journals (Sweden)

    Lin Li

    Full Text Available The aim of this study was to characterize the prevalence of extended-spectrum β-lactamase (ESBL genes and plasmid-mediated fluoroquinolone resistance (PMQR determinants in 202 Escherichia coli isolates from chickens in Anhui Province, China, and to determine whether ESBL and PMQR genes co-localized in the isolates. Antimicrobial susceptibility for 12 antimicrobials was determined by broth microdilution. Polymerase chain reactions (PCRs, DNA sequencing, and pulsed field gel electrophoresis (PFGE were employed to characterize the molecular basis for β-lactam and fluoroquinolone resistance. High rates of antimicrobial resistance were observed, 147 out of the 202 (72.8% isolates were resistant to at least 6 antimicrobial agents and 28 (13.9% of the isolates were resistant to at least 10 antimicrobials. The prevalence of blaCTX-M, blaTEM-1 and blaTEM-206 genes was 19.8%, 24.3% and 11.9%, respectively. Seventy-five out of the 202 (37.1% isolates possessed a plasmid-mediated quinolone resistance determinant in the form of qnrS (n = 21; this determinant occurred occasionally in combination with aac(6'-1b-cr (n = 65. Coexistence of ESBL and/or PMQR genes was identified in 31 of the isolates. Two E. coli isolates carried blaTEM-1, blaCTX-M and qnrS, while two others carried blaCTX-M, qnrS and aac(6'-1b-cr. In addition, blaTEM-1, qnrS and aac(6'-1b-cr were co-located in two other E. coli isolates. PFGE analysis showed that these isolates were not clonally related and were genetically diverse. To the best of our knowledge, this study is the first to describe detection of TEM-206-producing E. coli in farmed chickens, and the presence of blaTEM-206, qnrS and aac(6'-1b-cr in one of the isolates.

  4. Escherichia coli mediated urinary tract infections: are there distinct uropathogenic E. coli (UPEC) pathotypes?

    Science.gov (United States)

    Marrs, Carl F; Zhang, Lixin; Foxman, Betsy

    2005-11-15

    A variety of virulence genes are associated with Escherichia coli mediated urinary tract infections. Particular sets of virulence factors shared by bacterial strains directing them through a particular pathogenesis process are called a "pathotype." Comparison of co-occurrence of potential urinary tract infection (UTI) virulence genes among different E. coli isolates from fecal and UTI collections provides evidence for multiple pathotypes of uropathogenic E. coli, but current understanding of critical genetic differences defining the pathotypes is limited. Discovery of additional E. coli genes involved in uropathogenesis and determination of their distribution and co-occurrences will further define UPEC pathotypes and allow for a more detailed analysis of how these pathotypes might differ in how they cause disease.

  5. The pangenome structure of Escherichia coli: comparative genomic analysis of E. coli commensal and pathogenic isolates.

    Science.gov (United States)

    Rasko, David A; Rosovitz, M J; Myers, Garry S A; Mongodin, Emmanuel F; Fricke, W Florian; Gajer, Pawel; Crabtree, Jonathan; Sebaihia, Mohammed; Thomson, Nicholas R; Chaudhuri, Roy; Henderson, Ian R; Sperandio, Vanessa; Ravel, Jacques

    2008-10-01

    Whole-genome sequencing has been skewed toward bacterial pathogens as a consequence of the prioritization of medical and veterinary diseases. However, it is becoming clear that in order to accurately measure genetic variation within and between pathogenic groups, multiple isolates, as well as commensal species, must be sequenced. This study examined the pangenomic content of Escherichia coli. Six distinct E. coli pathovars can be distinguished using molecular or phenotypic markers, but only two of the six pathovars have been subjected to any genome sequencing previously. Thus, this report provides a seminal description of the genomic contents and unique features of three unsequenced pathovars, enterotoxigenic E. coli, enteropathogenic E. coli, and enteroaggregative E. coli. We also determined the first genome sequence of a human commensal E. coli isolate, E. coli HS, which will undoubtedly provide a new baseline from which workers can examine the evolution of pathogenic E. coli. Comparison of 17 E. coli genomes, 8 of which are new, resulted in identification of approximately 2,200 genes conserved in all isolates. We were also able to identify genes that were isolate and pathovar specific. Fewer pathovar-specific genes were identified than anticipated, suggesting that each isolate may have independently developed virulence capabilities. Pangenome calculations indicate that E. coli genomic diversity represents an open pangenome model containing a reservoir of more than 13,000 genes, many of which may be uncharacterized but important virulence factors. This comparative study of the species E. coli, while descriptive, should provide the basis for future functional work on this important group of pathogens.

  6. Viabilidad de Escherichia coli en presencia de diferentes contaminantes

    Directory of Open Access Journals (Sweden)

    Antonio Rivera T

    2006-04-01

    Full Text Available La contaminación en ríos condiciona la presencia de microorganismos adaptados al ecosistema entre ellos a patógenos de importancia en salud pública. Objetivo: Determinar la viabilidad de Escherichia coli en presencia de nitrato de plata, carbonato de amonio, fenol y formaldehído. Materiales y métodos: Se tomaron muestras de agua del río Alseseca, que luego se sembró en medios de cultivo selectivos para enterobacterias, seleccionándose las colonias del género Escherichia, las cuales fueron sembradas en el medio de orientación CHROMagar ECC. Las muestras de E. coli se evaluaron en presencia de nitrato de plata, carbonato de amonio, fenol y formaldehído. Resultados: El grupo experimental presentó viabilidad en presencia de los cuatro compuestos, el grupo control positivo presentó nula viabilidad, la comparación entre los grupos mostró diferencia significativa (p< 0,05. Conclusión: Los aislamientos de E. coli mostraron viabilidad, implicando riesgos para el ecosistemas y la salud, ya que el río Alseseca atraviesa por el municipio de Puebla donde existen núcleos poblacionales importantes.

  7. Overexpression and export of Vibrio anguillarum metalloprotease in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Zhang Fengli; Chi Zhenming; Chen Jixiang; Wu Longfei; Liang Likun

    2007-01-01

    Vibrio anguillarum metalloprotease, an extracellular zinc metalloprotease involved in the virulence mechanism of Vibrio anguillarum, is synthesized from the empA gene as a 611-residue precursor and naturally secreted via Sec secretion pathway in Vibrio anguillarum. In this study, heterologous expression of the empA gene encoding metallopmtease and export of the recombinant metalloprotease in Escherichia coliwere examined. The empA gene was subcloned into pBAD24 with arabinose promoter and sequenced. The sequence encoded a polypeptide(611 amino acids)consisting of four domains: a signal peptide, an Nterminal propeptide, a mature region and a C-terminal propeptide. The empA gene inserted in plasmid pBAD24 was overexpressed in TOP10 strain of E. Coli after arabinose induction. The 36kDa polypeptide of the recombinant metalloprotease as the mature protease was further confirmed by SDS-PAGE and immunoblotting. It was found that recombinant metalloprotease with the EmpA activity and antigenicity wasexported into the periplasm of Escherichia coli cells via Sec translocation pathway, whereas it was secreted into extracellular environments in V. Anguillarum. The results imply that the expression, export and processing mechanism of the protein in E. Coli are similar to those in V. Anguillarum.

  8. Persistence of Escherichia coli in batch and continuous vermicomposting systems.

    Science.gov (United States)

    Hénault-Ethier, Louise; Martin, Vincent J J; Gélinas, Yves

    2016-10-01

    Vermicomposting is a biooxidation process in which epigeicearthworms act in synergy with microbial populations to degrade organic matter. Vermicomposting does not go through a thermophilic stage as required by North American legislations for pathogen eradication. We examined the survival of a Green Fluorescent Protein (GFP) labeled Escherichia coli MG1655 as a model for the survival of pathogenic bacteria in both small-scale batch and medium-scale continuously-operated systems to discern the influence of the earthworm Eisenia fetida, nutrient content and the indigenous vermicompost microbial community on pathogen abundance. In batch systems, the microbial community had the greatest influence on the rapid decline of E. coli populations, and the effect of earthworms was only visible in microbially-impoverishedvermicomposts. No significant earthworm density-dependent relationship was observed on E. coli survival under continuous operation. E. coli numbers decreased below the US EPA compost sanitation guidelines of 10(3)Colony Forming Units (CFU)/g (dry weight) within 18-21days for both the small-scale batch and medium-scale continuous systems, but it took up to 51days without earthworms and with an impoverished microbial community to reach the legal limit. Nutrient replenishment (i.e. organic carbon) provided by continuous feed input did not appear to extend E. coli survival. In fact, longer survival of E. coli was noticed in treatments where less total and labile sugars were available, suggesting that sugars may support potentially antagonist bacteria in the vermicompost. Total N, pH and humidity did not appear to affect E. coli survival. Several opportunistic human pathogens may be found in vermicompost, and their populations are likely kept in check by antagonists.

  9. Reduction of verotoxigenic Escherichia coli in production of fermented sausages.

    Science.gov (United States)

    Holck, Askild L; Axelsson, Lars; Rode, Tone Mari; Høy, Martin; Måge, Ingrid; Alvseike, Ole; L'abée-Lund, Trine M; Omer, Mohamed K; Granum, Per Einar; Heir, Even

    2011-11-01

    After a number of foodborne outbreaks of verotoxigenic Escherichia coli involving fermented sausages, some countries have imposed regulations on sausage production. For example, the US Food Safety and Inspection Service requires a 5 log(10) reduction of E. coli in fermented products. Such regulations have led to a number of studies on the inactivation of E. coli in fermented sausages by changing processing and post-processing conditions. Several factors influence the survival of E. coli such as pre-treatment of the meat, amount of NaCl, nitrite and lactic acid, water activity, pH, choice of starter cultures and addition of antimicrobial compounds. Also process variables like fermentation temperature and storage time play important roles. Though a large variety of different production processes of sausages exist, generally the reduction of E. coli caused by production is in the range 1-2 log(10). In many cases this may not be enough to ensure microbial food safety. By optimising ingredients and process parameters it is possible to increase E. coli reduction to some extent, but in some cases still other post process treatments may be required. Such treatments may be storage at ambient temperatures, specific heat treatments, high pressure processing or irradiation. HACCP analyses have identified the quality of the raw materials, low temperature in the batter when preparing the sausages and a rapid pH drop during fermentation as critical control points in sausage production. This review summarises the literature on the reduction verotoxigenic E. coli in production of fermented sausages.

  10. Sub-inhibitory concentrations of vancomycin prevent quinolone-resistance in a penicillin-resistant isolate of Streptococcus pneumoniae

    Directory of Open Access Journals (Sweden)

    Moreillon Philippe

    2001-07-01

    Full Text Available Abstract Background The continuous spread of penicillin-resistant pneumococci represents a permanent threat in the treatment of pneumococcal infections, especially when strains show additional resistance to quinolones. The main objective of this study was to determine a treatment modality impeding the emergence of quinolone resistance. Results Exposure of a penicillin-resistant pneumococcus to increasing concentrations of trovafloxacin or ciprofloxacin selected for mutants resistant to these drugs. In the presence of sub-inhibitory concentrations of vancomycin, development of trovafloxacin-resistance and high-level ciprofloxacin-resistance were prevented. Conclusions Considering the risk of quinolone-resistance in pneumococci, the observation might be of clinical importance.

  11. Characterization of quinolone resistance in Salmonella spp. isolates from food products and human samples in Brazil

    Science.gov (United States)

    Pribul, Bruno Rocha; Festivo, Marcia Lima; de Souza, Miliane Moreira Soares; dos Prazeres Rodrigues, Dalia

    2016-01-01

    Non-typhoidal salmonellosis is an important zoonotic disease caused by Salmonella enterica. The aim of this study was to investigate the prevalence of plasmid-mediated quinolone resistance in Salmonella spp. and its association with fluoroquinolone susceptibility in Brazil. A total of 129 NTS isolates (samples from human origin, food from animal origin, environmental, and animal) grouped as from animal (n = 62) and human (n = 67) food were evaluated between 2009 and 2013. These isolates were investigated through serotyping, antimicrobial susceptibility testing, and the presence of plasmid-mediated quinolone resistance (PMQR) genes (qnr, aac(6′)-Ib) and associated integron genes (integrase, and conserved integron region). Resistance to quinolones and/or fluoroquinolones, from first to third generations, was observed. Fifteen isolates were positive for the presence of qnr genes (8 qnrS, 6 qnrB, and 1 qnrD) and twenty three of aac(6′)-Ib. The conserved integron region was detected in 67 isolates as variable regions, from ±600 to >1000 pb. The spread of NTS involving PMQR carriers is of serious concern and should be carefully monitored. PMID:26887245

  12. Characterization of quinolone resistance in Salmonella spp. isolates from food products and human samples in Brazil.

    Science.gov (United States)

    Pribul, Bruno Rocha; Festivo, Marcia Lima; de Souza, Miliane Moreira Soares; Rodrigues, Dalia dos Prazeres

    2016-01-01

    Non-typhoidal salmonellosis is an important zoonotic disease caused by Salmonella enterica. The aim of this study was to investigate the prevalence of plasmid-mediated quinolone resistance in Salmonella spp. and its association with fluoroquinolone susceptibility in Brazil. A total of 129 NTS isolates (samples from human origin, food from animal origin, environmental, and animal) grouped as from animal (n=62) and human (n=67) food were evaluated between 2009 and 2013. These isolates were investigated through serotyping, antimicrobial susceptibility testing, and the presence of plasmid-mediated quinolone resistance (PMQR) genes (qnr, aac(6')-Ib) and associated integron genes (integrase, and conserved integron region). Resistance to quinolones and/or fluoroquinolones, from first to third generations, was observed. Fifteen isolates were positive for the presence of qnr genes (8 qnrS, 6 qnrB, and 1 qnrD) and twenty three of aac(6')-Ib. The conserved integron region was detected in 67 isolates as variable regions, from ±600 to >1000pb. The spread of NTS involving PMQR carriers is of serious concern and should be carefully monitored.

  13. Structural insights into the quinolone resistance mechanism of Mycobacterium tuberculosis DNA gyrase.

    Directory of Open Access Journals (Sweden)

    Jérémie Piton

    Full Text Available Mycobacterium tuberculosis DNA gyrase, an indispensable nanomachine involved in the regulation of DNA topology, is the only type II topoisomerase present in this organism and is hence the sole target for quinolone action, a crucial drug active against multidrug-resistant tuberculosis. To understand at an atomic level the quinolone resistance mechanism, which emerges in extensively drug resistant tuberculosis, we performed combined functional, biophysical and structural studies of the two individual domains constituting the catalytic DNA gyrase reaction core, namely the Toprim and the breakage-reunion domains. This allowed us to produce a model of the catalytic reaction core in complex with DNA and a quinolone molecule, identifying original mechanistic properties of quinolone binding and clarifying the relationships between amino acid mutations and resistance phenotype of M. tuberculosis DNA gyrase. These results are compatible with our previous studies on quinolone resistance. Interestingly, the structure of the entire breakage-reunion domain revealed a new interaction, in which the Quinolone-Binding Pocket (QBP is blocked by the N-terminal helix of a symmetry-related molecule. This interaction provides useful starting points for designing peptide based inhibitors that target DNA gyrase to prevent its binding to DNA.

  14. Genome Sequence of the Enterohemorrhagic Escherichia coli Bacteriophage UFV-AREG1

    Science.gov (United States)

    Batalha, Laís Silva; Albino, Luiz Augusto A.; Boggione, Delaine Meireles Gouveia; Gontijo, Marco Tulio Pardini; Bazzolli, Denise M. Soares; Mendonca, Regina C. Santos

    2016-01-01

    Here, we present the genome sequence of the Escherichia coli bacteriophage UFV-AREG1. This phage was isolated from cowshed wastewater and showed specificity for enterohemorrhagic E. coli O157:H7 (ATCC 43895), E. coli 0111 (CDC O11ab) and E. coli (ATCC 23229). PMID:27738021

  15. Multiplex PCR for Diagnosis of Enteric Infections Associated with Diarrheagenic Escherichia coli

    Science.gov (United States)

    Vidal, Roberto; Vidal, Maricel; Lagos, Rossana; Levine, Myron; Prado, Valeria

    2004-01-01

    A multiplex PCR for detection of three categories of diarrheagenic Escherichia coli was developed. With this method, enterohemorrhagic E. coli, enteropathogenic E. coli, and enterotoxigenic E. coli were identified in fecal samples from patients with hemorrhagic colitis, watery diarrhea, or hemolytic-uremic syndrome and from food-borne outbreaks. PMID:15071051

  16. Diarrhea, Urosepsis and Hemolytic Uremic Syndrome Caused by the Same Heteropathogenic Escherichia coli Strain.

    Science.gov (United States)

    Ang, C Wim; Bouts, Antonia H M; Rossen, John W A; Van der Kuip, Martijn; Van Heerde, Marc; Bökenkamp, Arend

    2016-09-01

    We describe an 8-month-old girl with diarrhea, urosepsis and hemolytic uremic syndrome caused by Escherichia coli. Typing of cultured E. coli strains from urine and blood revealed the presence of virulence factors from multiple pathotypes of E. coli. This case exemplifies the genome plasticity of E. coli and the resulting heteropathogenic strains.

  17. A putative, novel coli surface antigen 8B (CS8B) of enterotoxigenic Escherichia coli.

    Science.gov (United States)

    Njoroge, Samuel M; Boinett, Christine J; Madé, Laure F; Ouko, Tom T; Fèvre, Eric M; Thomson, Nicholas R; Kariuki, Samuel

    2015-10-01

    Enterotoxigenic Escherichia coli (ETEC) strains harbor multiple fimbriae and pili to mediate host colonization, including the type IVb pilus, colonization factor antigen III (CFA/III). Not all colonization factors are well characterized or known in toxin positive ETEC isolates, which may have an impact identifying ETEC isolates based on molecular screening of these biomarkers. We describe a novel coli surface antigen (CS) 8 subtype B (CS8B), a family of CFA/III pilus, in a toxin producing ETEC isolate from a Kenyan collection. In highlighting the existence of this putative CS, we provide the sequence and specific primers, which can be used alongside other ETEC primers previously described.

  18. Effect of bile on growth, peritoneal absorption, and blood clearance of Escherichia coli in E coli peritonitis

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, R.; Schalen, C.; Tranberg, K.G. (Department of Surgery, Lund University, Lund (Sweden))

    1991-06-01

    The effect of intraperitoneal bile on growth, peritoneal absorption, and clearance of Escherichia coli was determined in E coli peritonitis in the rat. In E coli peritonitis, intraperitoneal bacterial counts gradually decreased, whereas they increased (after 2 hours) with subsequent development of bacteremia in E coli plus bile peritonitis. After an intraperitoneal injection of labeled bacteria, blood radioactivity was only initially lower in E coli plus bile peritonitis compared with E coli peritonitis. Clearance from blood was lower in E coli plus bile peritonitis than in E coli peritonitis. Organ localization was similar in E coli peritonitis and E coli plus bile peritonitis with decreased splenic, increased pulmonary, and unchanged hepatic uptakes compared with controls. Impaired peritoneal absorption of bacteria, together with impaired local host defense, is likely to enhance the noxious effect of bile in E coli peritonitis.

  19. Posttranslational Modifications of Ribosomal Proteins in Escherichia coli.

    Science.gov (United States)

    Nesterchuk, M V; Sergiev, P V; Dontsova, O A

    2011-04-01

    А number of ribosomal proteins inEscherichia coliundergo posttranslational modifications. Six ribosomal proteins are methylated (S11, L3, L11, L7/L12, L16, and L33), three proteins are acetylated (S5, S18, and L7), and protein S12 is methylthiolated. Extra amino acid residues are added to protein S6. С-terminal amino acid residues are partially removed from protein L31. The functional significance of these modifications has remained unclear. These modifications are not vital to the cells, and it is likely that they have regulatory functions. This paper reviews all the known posttranslational modifications of ribosomal proteins inEscherichia coli. Certain enzymes responsible for the modifications and mechanisms of enzymatic reactions are also discussed.

  20. CRISPR adaptation in Escherichia coli subtypeI-E system.

    Science.gov (United States)

    Kiro, Ruth; Goren, Moran G; Yosef, Ido; Qimron, Udi

    2013-12-01

    The CRISPRs (clustered regularly interspaced short palindromic repeats) and their associated Cas (CRISPR-associated) proteins are a prokaryotic adaptive defence system against foreign nucleic acids. The CRISPR array comprises short repeats flanking short segments, called 'spacers', which are derived from foreign nucleic acids. The process of spacer insertion into the CRISPR array is termed 'adaptation'. Adaptation allows the system to rapidly evolve against emerging threats. In the present article, we review the most recent studies on the adaptation process, and focus primarily on the subtype I-E CRISPR-Cas system of Escherichia coli.

  1. Composition of cardiolipin molecular species in Escherichia coli.

    OpenAIRE

    Yokota, K; Kanamoto, R.; Kito, M

    1980-01-01

    The composition of the molecular species of acidic phospholipids in Escherichia coli B during the late exponential growth phase at 37 degrees C was determined. Two phosphatidyl groups of cardiolipin, the 3-(3-sn-phosphatidyl) and 1-(3-sn-phosphatidyl) moieties of cardiolipin, were isolated by limited hydrolysis with phospholipase C. No significant difference in the composition of the molecular species was found between the 3-(3-sn-phosphatidyl) and 1-(3-sn-phosphatidyl) moieties. On the other...

  2. Pengujian Bakteri Escherichia Coli Pada Air Sumur Di Medan Johor

    OpenAIRE

    Mahardhika, Diah

    2013-01-01

    Water is an essential material in life. Water is a means to improve public health. The spread of water borne diseases can be. Water pollution can be caused due to the entry of human and animal waste, but it can also be caused directly or through a leak or where ground soil cracks. This test aims to determine the number most likely Most Probable Number (MPN) Escherichia coli bacteria that contaminate well water located in Medan Johor still meet water quality requirements or not. The samplin...

  3. Modulation of allele leakiness and adaptive mutability in Escherichia coli

    Indian Academy of Sciences (India)

    R. Jayaraman

    2000-08-01

    It is shown that partial phenotypic suppression of two ochre mutations (argE3 and lacZU118) and an amber mutation (in argE) by sublethal concentrations of streptomycin in an rpsL+ (streptomycin-sensitive) derivative of the Escherichia coli strain AB1157 greatly enhances their adaptive mutability under selection. Streptomycin also increases adaptive mutability brought about by the ppm mutation described earlier. Inactivation of recA affects neither phenotypic suppression by streptomycin nor replication-associated mutagenesis but abolishes adaptive mutagenesis. These results indicate a causal relationship between allele leakiness and adaptive mutability.

  4. Precursor for elongation factor Tu from Escherichia coli.

    OpenAIRE

    1986-01-01

    The tufA gene, one of two genes in Escherichia coli encoding elongation factor Tu (EF-Tu), was cloned into a ColE1-derived plasmid downstream of the lac promoter-operator. In cells carrying this plasmid, the synthesis of EF-Tu was increased four- to fivefold upon the addition of isopropyl-beta-D-thiogalactopyranoside (an inducer of the lac promoter). This condition led to the synthesis of a novel protein, called pTu, which comigrated with EF-Tu on a sodium dodecyl sulfate-polyacrylamide gel b...

  5. Interactions between Phage-Shock Proteins in Escherichia coli

    OpenAIRE

    Adams, Hendrik; Teertstra, Wieke; Demmers, Jeroen; Boesten, Rolf; Tommassen, Jan

    2003-01-01

    Expression of the pspABCDE operon of Escherichia coli is induced upon infection by filamentous phage and by many other stress conditions, including defects in protein export. Expression of the operon requires the alternative sigma factor σ54 and the transcriptional activator PspF. In addition, PspA plays a negative regulatory role, and the integral-membrane proteins PspB and PspC play a positive one. In this study, we investigated whether the suggested protein-protein interactions implicated ...

  6. PspA can form large scaffolds in Escherichia coli.

    Science.gov (United States)

    Standar, Kerstin; Mehner, Denise; Osadnik, Hendrik; Berthelmann, Felix; Hause, Gerd; Lünsdorf, Heinrich; Brüser, Thomas

    2008-10-29

    The phage shock protein A (PspA) of Escherichia coli stabilizes the cytoplasmic membrane under stress conditions. Here we demonstrate that PspA can form hollow spherical or prolate spheroidal particles of about 30-40nm diameter with a scaffold-like arrangement of protein subunits at the surface. The 'PspA-scaffold' is the basic structure that is common to all particles. The PspA-scaffold may be of fundamental importance, as it could allow PspA to stabilize the integrity of membranes through numerous contact points over a large surface area.

  7. PspA can form large scaffolds in Escherichia coli.

    OpenAIRE

    Standar, Kerstin; Mehner, Denise; Osadnik, Hendrik; Berthelmann, Felix; Hause, Gerd; Lünsdorf, Heinrich; Brüser, Thomas

    2008-01-01

    The phage shock protein A (PspA) of Escherichia coli stabilizes the cytoplasmic membrane under stress conditions. Here we demonstrate that PspA can form hollow spherical or prolate spheroidal particles of about 30-40nm diameter with a scaffold-like arrangement of protein subunits at the surface. The 'PspA-scaffold' is the basic structure that is common to all particles. The PspA-scaffold may be of fundamental importance, as it could allow PspA to stabilize the integrity of membranes through n...

  8. Isolation and mapping of phosphotransferase mutants in Escherichia coli.

    Science.gov (United States)

    Epstein, W; Jewett, S; Fox, C F

    1970-11-01

    Mutants of Escherichia coli K-12 defective in enzyme I or Hpr, the two common components of the phosphoenolpyruvate-dependent phosphotransferase system, were isolated by a simple, direct method. The ptsI locus, the structural gene for enzyme I, and the ptsH locus, the site of mutations leading to loss of Hpr activity, are adjacent genes and could be part of a single operon. These two genes lie between the purC and supN markers in the order: strA... guaB-purC-ptsI-ptsH-supN-dsdA... his.

  9. Penicillin-binding site on the Escherichia coli cell envelope.

    OpenAIRE

    Amaral, L; Lee, Y.; Schwarz, U.; Lorian, V

    1986-01-01

    The binding of 35S-labeled penicillin to distinct penicillin-binding proteins (PBPs) of the "cell envelope" obtained from the sonication of Escherichia coli was studied at different pHs ranging from 4 to 11. At low pH, PBPs 1b, 1c, 2, and 3 demonstrated the greatest amount of binding. At high pH, these PBPs bound the least amount of penicillin. PBPs 1a and 5/6 exhibited the greatest amount of binding at pH 10 and the least amount at pH 4. With the exception of PBP 5/6, the effect of pH on the...

  10. Modeling Surface Growth of Escherichia coli on Agar Plates

    OpenAIRE

    Fujikawa, Hiroshi; Morozumi, Satoshi

    2005-01-01

    Surface growth of Escherichia coli cells on a membrane filter placed on a nutrient agar plate under various conditions was studied with a mathematical model. The surface growth of bacterial cells showed a sigmoidal curve with time on a semilogarithmic plot. To describe it, a new logistic model that we presented earlier (H. Fujikawa et al., Food Microbiol. 21:501-509, 2004) was modified. Growth curves at various constant temperatures (10 to 34°C) were successfully described with the modified m...

  11. Modeling the pressure inactivation dynamics of Escherichia coli

    Directory of Open Access Journals (Sweden)

    Yamamoto K.

    2005-01-01

    Full Text Available Escherichia coli, as a model microorganism, was treated in phosphate-buffered saline under high hydrostatic pressure between 100 and 300 MPa, and the inactivation dynamics was investigated from the viewpoint of predictive microbiology. Inactivation data were curve fitted by typical predictive models: logistic, Gompertz and Weibull functions. Weibull function described the inactivation curve the best. Two parameters of Weibull function were calculated for each holding pressure and their dependence on holding pressure was obtained by interpolation. With the interpolated parameters, inactivation curves were simulated and compared with the experimental data sets.

  12. [Hemolytic uremic syndrome caused by enterohaemorrhagic Escherichia coli].

    Science.gov (United States)

    Ibarra, Cristina; Goldstein, Jorge; Silberstein, Claudia; Zotta, Elsa; Belardo, Marcela; Repetto, Horacio A

    2008-10-01

    Hemolytic uremic syndrome (HUS) is characterized by microangiopathic hemolytic anemia, plaquetopenia and kidney damage. It is the leading cause of acute renal failure in pediatric age and the second for chronic renal failure. Shiga toxin-producing Escherichia coli (STEC) is the first etiologic agent of HUS being its main reservoir cattle and transmitted via contaminated food. At present, there is no specific treatment to reduce the progression of HUS. The study of the mechanisms by which STEC infects and Shiga toxin induces HUS can help to find new strategies to prevent this disease.

  13. Resistencia a biocidas de diferentes cepas de escherichia coli

    OpenAIRE

    López Aguayo, M. Carmen; Grande Burgos, M. José; Lucas López, R.; Gálvez-del-Postigo-Ruiz, Antonio

    2010-01-01

    Los biocidas son herramientas de gran importancia para controlar la transmisión de microorganismos patógenos a través de la cadena alimentaria. En el presente estudio se ha determinado la resistencia a siete biocidas en una colección de nueve cepas de Escherichia coli, incluyendo cepas verotoxigénicas y cepas portadoras de resistencia a beta-lactámicos. Los biocidas más eficaces fueron triclosan, hexadecilpiridinio y cetrimida, seguido del cloruro de benzalconio. No se encon...

  14. Genome-scale genetic engineering in Escherichia coli.

    Science.gov (United States)

    Jeong, Jaehwan; Cho, Namjin; Jung, Daehee; Bang, Duhee

    2013-11-01

    Genome engineering has been developed to create useful strains for biological studies and industrial uses. However, a continuous challenge remained in the field: technical limitations in high-throughput screening and precise manipulation of strains. Today, technical improvements have made genome engineering more rapid and efficient. This review introduces recent advances in genome engineering technologies applied to Escherichia coli as well as multiplex automated genome engineering (MAGE), a recent technique proposed as a powerful toolkit due to its straightforward process, rapid experimental procedures, and highly efficient properties.

  15. Engineering Escherichia coli Cell Factories for n-Butanol Production.

    Science.gov (United States)

    Dong, Hongjun; Zhao, Chunhua; Zhang, Tianrui; Lin, Zhao; Li, Yin; Zhang, Yanping

    2016-01-01

    The production of n-butanol, as a widely applied solvent and potential fuel, is attracting much attention. The fermentative production of butanol coupled with the production of acetone and ethanol by Clostridium (ABE fermentation) was once one of the oldest biotechnological processes, ranking second in scale behind ethanol fermentation. However, there remain problems with butanol production by Clostridium, especially the difficulty in genetically manipulating clostridial strains. In recent years, many efforts have been made to produce butanol using non-native strains. Until now, the most advanced effort was the engineering of the user-friendly and widely studied Escherichia coli for butanol production. This paper reviews the current progress and problems relating to butanol production by engineered E. coli in terms of prediction using mathematical models, pathway construction, novel enzyme replacement, butanol toxicity, and tolerance engineering strategies.

  16. Epidemiology and clinical manifestations of enteroaggregative Escherichia coli

    DEFF Research Database (Denmark)

    Hebbelstrup Jensen, Betina; Olsen, Katharina E P; Struve, Carsten

    2014-01-01

    Enteroaggregative Escherichia coli (EAEC) represents a heterogeneous group of E. coli strains. The pathogenicity and clinical relevance of these bacteria are still controversial. In this review, we describe the clinical significance of EAEC regarding patterns of infection in humans, transmission......, reservoirs, and symptoms. Manifestations associated with EAEC infection include watery diarrhea, mucoid diarrhea, low-grade fever, nausea, tenesmus, and borborygmi. In early studies, EAEC was considered to be an opportunistic pathogen associated with diarrhea in HIV patients and in malnourished children...... in developing countries. In recent studies, associations with traveler's diarrhea, the occurrence of diarrhea cases in industrialized countries, and outbreaks of diarrhea in Europe and Asia have been reported. In the spring of 2011, a large outbreak of hemolytic-uremic syndrome (HUS) and hemorrhagic colitis...

  17. Production and purification of active snowdrop lectin in Escherichia coli.

    Science.gov (United States)

    Longstaff, M; Powell, K S; Gatehouse, J A; Raemaekers, R; Newell, C A; Hamilton, W D

    1998-02-15

    Recombinant snowdrop lectin was produced in Escherichia coli from a cDNA clone encoding mature Galanthus nivalis agglutinin. After induction with isopropylthio-beta-D-galactoside, inclusion bodies from E. coli were solubilised and the G. nivalis agglutinin purified by metal-affinity chromatography using a carboxy-terminal hexahistidine tag. The protein was refolded on the metal-affinity column prior to elution. After purification, the recombinant G. nivalis agglutinin agglutinated rabbit erythrocytes to a dilution similar to that determined for 'native' lectin purified from snowdrop, and showed similar specific binding to mannose. The toxicity of the recombinant G. nivalis agglutinin towards rice brown planthopper (Nilaparvata lugens) was shown to be similar to that of 'native' G. nivalis agglutinin when incorporated into an artificial diet. The recombinant G. nivalis agglutinin is thus functionally similar to 'native' snowdrop lectin.

  18. Probability of recovering pathogenic Escherichia coli from foods.

    Science.gov (United States)

    Hill, W E; Ferreira, J L; Payne, W L; Jones, V M

    1985-01-01

    The probability of recovering pathogenic Escherichia coli from food by the Bacteriological Analytical Manual method was determined by the effects of several factors: the number of strains per food, the ability of pathogenic strains to survive enrichment, and the frequency of plasmid loss during enrichment. Biochemical patterns indicated the presence of about six E. coli strains per food sample. About half of the strains isolated from humans did not survive enrichment. Among those which grew, plasmid loss, as determined by gel electrophoresis and DNA colony hybridization, ranged from 20 to 95%. The combined effects of failure to survive enrichment and plasmid loss decreased the relative numbers of these strains and reduced the chance of detecting pathogens. To counteract this tendency and obtain a 90 to 95% probability off recovering a given pathogenic strain, 40 to 50 colonies per food sample should be picked during the routine testing of foods. PMID:3893320

  19. Bleomycin sensitivity in Escherichia coli is medium-dependent.

    Directory of Open Access Journals (Sweden)

    Tao Xu

    Full Text Available Bleomycin (BLM is a glycopeptide antibiotic and anti-tumor agent that targets primarily the furanose rings of DNA and in the presence of ferrous ions produces oxidative damage and DNA strand breaks. Escherichia coli cells growing in broth medium and exposed to low concentrations of BLM contain double-strand breaks and require homologous recombination to survive. To a lesser extent, the cells also require the abasic (AP endonucleases associated with base excision repair, presumably to repair oxidative damage. As expected, there is strong induction of the SOS system in treated cells. In contrast, E. coli cells growing in glucose or glycerol minimal medium are resistant to the lethal action of BLM and do not require either homologous recombination functions or AP-endonucleases for survival. DNA ligase activity, however, is needed for cells growing in minimal medium to resist the lethal effects of BLM. There is weak SOS induction in such treated cells.

  20. Rotational tumbling of Escherichia coli aggregates under shear

    CERN Document Server

    Portela, R; Almeida, P L; Sobral, R G; Franco, J M; Leal, C R

    2016-01-01

    Growing living cultures of Escherichia coli bacteria were investigated using real-time in situ rheology and rheo-imaging measurements. In the early stages of growth (lag phase), and when subjected to a constant stationary shear, the viscosity slowly increases with the cell's population. As the bacteria reach the exponential phase of growth, the viscosity increases rapidly, with sudden and temporary abrupt decreases and recoveries. At a certain stage, corresponding grossly to the late phase of growth, when the population stabilises, the viscosity also keeps its maximum constant value, with drops and recoveries, for a long period of time. This complex rheological behaviour, which was observed to be shear strain dependent, is a consequence of two coupled effects: the cell density continuous increase and its changing interacting properties. Particular attention was given to the late phase of growth of E. coli populations under shear. Rheo-imaging measurements revealed, near the static plate, a rotational motion o...

  1. Biosensing Vibrio cholerae with Genetically Engineered Escherichia coli.

    Science.gov (United States)

    Holowko, Maciej B; Wang, Huijuan; Jayaraman, Premkumar; Poh, Chueh Loo

    2016-11-18

    Cholera is a potentially mortal, infectious disease caused by Vibrio cholerae bacterium. Current treatment methods of cholera still have limitations. Beneficial microbes that could sense and kill the V. cholerae could offer potential alternative to preventing and treating cholera. However, such V. cholerae targeting microbe is still not available. This microbe requires a sensing system to be able to detect the presence of V. cholera bacterium. To this end, we designed and created a synthetic genetic sensing system using nonpathogenic Escherichia coli as the host. To achieve the system, we have moved proteins used by V. cholerae for quorum sensing into E. coli. These sensor proteins have been further layered with a genetic inverter based on CRISPRi technology. Our design process was aided by computer models simulating in vivo behavior of the system. Our sensor shows high sensitivity to presence of V. cholerae supernatant with tight control of expression of output GFP protein.

  2. Substrate specificity engineering of Escherichia coli derived fructosamine 6-kinase.

    Science.gov (United States)

    Kojima, Katsuhiro; Mikami-Sakaguchi, Akane; Kameya, Miho; Miyamoto, Yusuke; Ferri, Stefano; Tsugawa, Wakako; Sode, Koji

    2013-02-01

    A three-dimensional structural model of Escherichia coli fructosamine 6-kinase (FN6K), an enzyme that phosphorylates fructosamines at C6 and catalyzes the production of the fructosamine 6-phosphate stable intermediate, was generated using the crystal structure of 2-keto-3-deoxygluconate kinase isolated from Thermus thermophilus as template. The putative active site region was then investigated by site-directed mutagenesis to reveal several amino acid residues that likely play important roles in the enzyme reaction. Met220 was identified as a residue that plays a role in substrate recognition when compared to Bacillus subtilis derived FN6K, which shows different substrate specificity from the E. coli FN6K. Among the various Met220-substituted mutant enzymes, Met220Leu, which corresponded to the B. subtilis residue, resulted in an increased activity of fructosyl-valine and decreased activity of fructosyl-lysine, thus increasing the specificity for fructosyl-valine by 40-fold.

  3. In Vivo study of naturally deformed Escherichia coli bacteria.

    Science.gov (United States)

    Tavaddod, Sharareh; Naderi-Manesh, Hossein

    2016-06-01

    A combination of light-microscopy and image processing has been applied to study naturally deformed Escherichia coli under in vivo condition and at the order of sub-pixel high-resolution accuracy. To classify deflagellated non-dividing E. coli cells to the rod-shape and bent-shape, a geometrical approach has been applied. From the analysis of the geometrical data which were obtained of image processing, we estimated the required effective energy for shaping a rod-shape to a bent-shape with the same size. We evaluated the energy of deformation in the naturally deformed bacteria with minimum cell manipulation, under in vivo condition, and with minimum influence of any external force, torque and pressure. Finally, we have also elaborated on the possible scenario to explain how naturally deformed bacteria are formed from initial to final-stage.

  4. Engineering Escherichia coli for improved ethanol production from gluconate.

    Science.gov (United States)

    Hildebrand, Amanda; Schlacta, Theresa; Warmack, Rebeccah; Kasuga, Takao; Fan, Zhiliang

    2013-10-10

    We report on engineering Escherichia coli to produce ethanol at high yield from gluconic acid (gluconate). Knocking out genes encoding for the competing pathways (l-lactate dehydrogenase and pyruvate formate lyase A) in E. coli KO11 eliminated lactate production, lowered the carbon flow toward acetate production, and improved the ethanol yield from 87.5% to 97.5% of the theoretical maximum, while the growth rate of the mutant strain was about 70% of the wild type. The corresponding genetic modifications led to a small improvement of ethanol yield from 101.5% to 106.0% on glucose. Deletion of the pyruvate dehydrogenase gene (pdh) alone improved the ethanol yield from 87.5% to 90.4% when gluconate was a substrate. The growth rate of the mutant strain was identical to that of the wild type. The corresponding genetic modification led to no improvements on ethanol yield on glucose.

  5. Metabolite essentiality elucidates robustness of Escherichia coli metabolism

    CERN Document Server

    Kim, Pan-Jun; Kim, Tae Yong; Lee, Kwang Ho; Jeong, Hawoong; Lee, Sang Yup; Park, Sunwon

    2007-01-01

    Complex biological systems are very robust to genetic and environmental changes at all levels of organization. Many biological functions of Escherichia coli metabolism can be sustained against single-gene or even multiple-gene mutations by using redundant or alternative pathways. Thus, only a limited number of genes have been identified to be lethal to the cell. In this regard, the reaction-centric gene deletion study has a limitation in understanding the metabolic robustness. Here, we report the use of flux-sum, which is the summation of all incoming or outgoing fluxes around a particular metabolite under pseudo-steady state conditions, as a good conserved property for elucidating such robustness of E. coli from the metabolite point of view. The functional behavior, as well as the structural and evolutionary properties of metabolites essential to the cell survival, was investigated by means of a constraints-based flux analysis under perturbed conditions. The essential metabolites are capable of maintaining a...

  6. SILVER NANOPARTICLES-DISK DIFFUSION TEST AGAINST Escherichia coli ISOLATES

    Science.gov (United States)

    CUNHA, Francisco Afrânio; MAIA, Kamila Rocha; MALLMAN, Eduardo José Jucá; CUNHA, Maria da Conceição dos Santos Oliveira; MACIEL, Antonio Auberson Martins; de SOUZA, Ieda Pereira; MENEZES, Everardo Albuquerque; FECHINE, Pierre Basílio Almeida

    2016-01-01

    SUMMARY Nanotechnology can be a valuable ally in the treatment of infections. Silver nanoparticles (AgNPs) are structures that have antimicrobial activity. The aim of this study was to produce AgNPs by green methods, characterize these structures, and assess their antimicrobial activity against Escherichia coli associated with the antibiotic ciprofloxacin. AgNPs were characterized by spectroscopic and microscopic techniques. Antimicrobial activity was evaluated by the disk diffusion method against 10 strains of E. coli. The synthesized AgNPs showed a spherical shape and a size of 85.07 ± 12.86 nm (mean ± SD). AgNPs increased the activity of ciprofloxacin by 40% and may represent a new therapeutic option for the treatment of bacterial infections. PMID:27680178

  7. The action of beta-galactosidase (Escherichia coli) on allolactose.

    Science.gov (United States)

    Huber, R E; Wallenfels, K; Kurz, G

    1975-09-01

    The parameters involved in the action of beta-galactosidase (EC 3.2.1.23) (Escherichia coli) on allolactose, the natural inducer of lac operon in E. coli, were studied. At low allolactose concentrations only galactose and glucose were formed, while at high allolactose concentrations transgalactolytic oligosaccharides were also produced. Detectable amounts of lactose were not formed. The V and Km values (49.6 U/mg and 0.00120 M, respectively) indicated that allolactose is as good if not a better substrate of beta-galactosidase as lactose. The pH optimum with allolactose (7.8-7.9) as well as its activation by K+ (as compared to activation by Na+) were similar to the case with lactose as substrate. The alpha-anomer of allolactose was hydrolyzed about two times as rapidly as was the beta-anomer.

  8. Mutational analysis of UMP kinase from Escherichia coli.

    Science.gov (United States)

    Bucurenci, N; Serina, L; Zaharia, C; Landais, S; Danchin, A; Bârzu, O

    1998-02-01

    UMP kinase from Escherichia coli is one of the four regulatory enzymes involved in the de novo biosynthetic pathway of pyrimidine nucleotides. This homohexamer, with no counterpart in eukarya, might serve as a target for new antibacterial drugs. Although the bacterial enzyme does not show sequence similarity with any other known nucleoside monophosphate kinase, two segments between amino acids 35 to 78 and 145 to 194 exhibit 28% identity with phosphoglycerate kinase and 30% identity with aspartokinase, respectively. Based on these similarities, a number of residues of E. coli UMP kinase were selected for site-directed mutagenesis experiments. Biochemical, kinetic, and spectroscopic analysis of the modified proteins identified residues essential for catalysis (Asp146), binding of UMP (Asp174), and interaction with the allosteric effectors, GTP and UTP (Arg62 and Asp77).

  9. Escherichia coli bacteraemia in patients with and without haematological malignancies

    DEFF Research Database (Denmark)

    Olesen, B; Kolmos, H J; Orskov, F

    1998-01-01

    We compared serotypes, virulence factors and susceptibility to antibiotics of Escherichia coli strains isolated from 282 patients with bacteraemia. Thirty-five of these were neutropenic patients with haematological malignancy and 247 were patients with a normal or raised total white blood cell...... in the two groups of strains. The haematological patients more often than the non-haematological patients had an unknown focus of infection, recurrent bacteraemia, shorter intervals between recurrences and recurrences caused by identical strains. Despite a well-defined focus, six of eight non......-haematological patients had recurrences with a strain different from the strain isolated in a previous episode. A possible connection between shorter intervals and recurrence with identical strains is discussed. We suggest that strains from recurrent E. coli bacteraemia are sent to a reference laboratory for serotyping...

  10. PRODUCTION OF RECOMBINANT PROTEIN CRM197 IN ESCHERICHIA COLI

    Directory of Open Access Journals (Sweden)

    I. V. Dukhovlinov

    2015-01-01

    Full Text Available The CRM197 is a non-toxic mutant of diphtheria toxin having a single amino acid substitution of a glycine for a glutamic acid in position 52. Being naturally nontoxic, CRM197 is a promising adjuvant and ideal carrier protein for conjugate vaccines. Typically, production of diphtheria toxin and some of the non-toxic proteins are carried out by Corynebacterium diphtheriae. Production of recombinant protein CRM197 in Escherichia coli is advantageous. It is simple, cheap and permits production of the target protein in a short time using a non-pathogenic microorganism. In this study patented high-yield-producing E. coli strain was used. As a part of the study the following steps were taken: protocol adjustment for induction of crm197 gene, production and purification of recombinant CRM197 by ion-exchange, hydrophobic and gel-filtration chromatography. The purity of the final preparation reached 97%.

  11. Assessment of Escherichia coli isolates for In vitro biofilm production

    Directory of Open Access Journals (Sweden)

    A.I. Dadawala

    Full Text Available A total of 14 Escherichia coli isolates were assessed for their ability to produce biofilm in-vitro by slime production on Congo red agar medium (CRA and microtitre plate assay. Out of 14 isolates tested, 12 were slime producing on CRA as indicated by black colonies. The isolates of E.coli varied in their ability to produce biofilm on the surface of microtitre plate ranging from 0.101 to 0.543 ODm. Out of 14 isolates tested, 10 were positive for biofilm production employing criterion of blank corrected ODs9s > 0.1. Two of slime negative isolated were also negative for biofilm production where as the two slime positive isolates were found to be negative for biofilm production. [Veterinary World 2010; 3(8.000: 364-366

  12. Purification of recombinant ovalbumin from inclusion bodies of Escherichia coli.

    Science.gov (United States)

    Upadhyay, Vaibhav; Singh, Anupam; Panda, Amulya K

    2016-01-01

    Recombinant ovalbumin expressed in bacterial host is essentially free from post-translational modifications and can be useful in understanding the structure-function relationship of the protein. In this study, ovalbumin was expressed in Escherichia coli in the form of inclusion bodies. Ovalbumin inclusion bodies were solubilized using urea and refolded by decreasing the urea concentration by dilution. Refolded protein was purified by anion exchange chromatography. Overall recovery of purified recombinant ovalbumin from inclusion bodies was about 30% with 98% purity. Purified recombinant ovalbumin was characterized by mass spectrometry, circular dichroism and fluorescence spectroscopy. Recombinant ovalbumin was shown to be resistant to trypsin using protease resistance assay. This indicated proper refolding of ovalbumin from inclusion bodies of E. coli. This method provides a simple way of producing ovalbumin free of post-translational modifications.

  13. Immunogenic Domains and Secondary Structure of Escherichia coli Recombinant Secreted Protein Escherichia coli-Secreted Protein B

    Directory of Open Access Journals (Sweden)

    Roxane Maria Fontes Piazza

    2017-04-01

    Full Text Available Several pathogenic bacteria are able to induce the attaching and effacing (A/E lesion. The A/E lesion is caused by effector proteins, such as Escherichia coli-secreted protein B (EspB, responsible together with Escherichia coli-secreted protein D for forming a pore structure on the host cell, which allows the translocation of effector proteins. Different variants of this protein can be found in E. coli strains, and during natural infection or when this protein is injected, this leads to variant-specific production of antibodies, which may not be able to recognize other variants of this bacterial protein. Herein, we describe the production of a hybrid recombinant EspB toxin that comprises all known variants of this protein. This recombinant protein could be useful as an antigen for the production of antibodies with broad-range detection of EspB-bearing bacteria, or as an antigen that could be used in vaccine formulation to generate antibodies against different EspB variants, thereby increasing immunization potential. In addition, the recombinant protein allowed us to analyze its secondary structure, to propose the immunogenic regions of EspB variants, and also to characterize anti-EspB antibodies. Our results suggest that this hybrid protein or a protein composed of the conserved immunogenic regions could be used for a variety of clinical applications.

  14. Immunogenic Domains and Secondary Structure of Escherichia coli Recombinant Secreted Protein Escherichia coli-Secreted Protein B.

    Science.gov (United States)

    Caetano, Bruna Alves; Rocha, Letícia Barboza; Carvalho, Eneas; Piazza, Roxane Maria Fontes; Luz, Daniela

    2017-01-01

    Several pathogenic bacteria are able to induce the attaching and effacing (A/E) lesion. The A/E lesion is caused by effector proteins, such as Escherichia coli-secreted protein B (EspB), responsible together with Escherichia coli-secreted protein D for forming a pore structure on the host cell, which allows the translocation of effector proteins. Different variants of this protein can be found in E. coli strains, and during natural infection or when this protein is injected, this leads to variant-specific production of antibodies, which may not be able to recognize other variants of this bacterial protein. Herein, we describe the production of a hybrid recombinant EspB toxin that comprises all known variants of this protein. This recombinant protein could be useful as an antigen for the production of antibodies with broad-range detection of EspB-bearing bacteria, or as an antigen that could be used in vaccine formulation to generate antibodies against different EspB variants, thereby increasing immunization potential. In addition, the recombinant protein allowed us to analyze its secondary structure, to propose the immunogenic regions of EspB variants, and also to characterize anti-EspB antibodies. Our results suggest that this hybrid protein or a protein composed of the conserved immunogenic regions could be used for a variety of clinical applications.

  15. Longitudinal characterization of Escherichia coli in healthy captive nonhuman primates

    Directory of Open Access Journals (Sweden)

    Jonathan B Clayton

    2014-11-01

    Full Text Available The gastrointestinal (GI tracts of nonhuman primates are well known to harbor Escherichia coli, a known commensal of humans and animals. While E. coli is a normal inhabitant of the mammalian gut, it also exists in a number of pathogenic forms or pathotypes, including those with predisposition for the GI tract, as well the urogenital tract. Diarrhea in captive nonhuman primates (NHPs has long been a problem in both zoo settings and research colonies, including the Como Zoo. It is an animal welfare concern, as well as a public health concern. E. coli has not been extensively studied in correlation with diarrhea in captive primates; therefore, a study was performed during the summer of 2009 in collaboration with a zoo in Saint Paul, MN, which was experiencing an increased incidence and severity of diarrhea among their NHP collection. Fresh fecal samples were collected weekly from each member of the primate collection, between June and August of 2009, and E. coli were isolated. A total of 33 individuals were included in the study, representing eight species. E. coli isolates were examined for their genetic relatedness, phylogenetic relationships, plasmid replicon types, virulence gene profiles, and antimicrobial susceptibility profiles. A number of isolates were identified containing virulence genes commonly found in several different E. coli pathotypes, and there was evidence of clonal transmission of isolates between animals and over time. Overall, the manifestation of chronic diarrhea in the Como Zoo primate collection is a complex problem whose solution will require regular screening for microbial agents and consideration of environmental causes. This study provides some insight towards the sharing of enteric bacteria between such animals.

  16. Streptokinase: cloning, expression, and excretion by Escherichia coli.

    Science.gov (United States)

    Malke, H; Ferretti, J J

    1984-06-01

    Genomic DNA from Streptococcus equisimilis strain H46A was cloned in Escherichia coli by using the bacteriophage lambda replacement vector L47 and an in vitro packaging system. A casein/plasminogen overlay technique was used to screen the phage bank for recombinants carrying the streptokinase gene ( skc ). The gene was present with a frequency of 1 in 836 recombinants, and 10 independent clones containing skc were isolated and physically characterized. One recombinant clone was used to subclone skc in E. coli plasmid vectors. Plasmid pMF2 [10.4 kilobases (kb)] consisting of pACYC184 with a 6.4-kb H46A DNA fragment in the EcoRI site and pMF5 (6.9 kb) carrying a 2.5-kb fragment in the Pst I site of pBR322 were among the recombinant plasmids determining streptokinase production in three different E. coli host strains. Expression of skc was independent of its orientation in either vector, indicating that its own promoter was present and functional in E. coli. However, expression in pBR322 was more efficient in one orientation than in the other, suggesting that one or both of the bla gene promoters contributed to skc expression. Several lines of evidence, including proof obtained by the immunodiffusion technique, established the identity of E. coli streptokinase. Testing cell-free culture supernatant fluids, osmotic shock fluids, and sonicates of osmotically shocked cells for streptokinase activity revealed the substance to be present in all three principal locations, indicating that E. coli cells were capable of releasing substantial amounts of streptokinase into the culture medium.

  17. Pathogenic Escherichia coli in rural household container waters.

    Science.gov (United States)

    Jagals, P; Barnard, T G; Mokoena, M M; Ashbolt, N; Roser, D J

    2013-01-01

    Plastic containers in the range of 5-20 L are widely used - especially in rural African settings - to collect, transport and store water for domestic use, including drinking, bathing and hygiene. The pathogen content of the waters in these containers has not been adequately characterized as yet. This paper presents the primary findings of a synoptic survey of drinking water quality samples from these containers and involved collection of bacterial indicator and pathogenicity gene data. In total, 571 samples of a variety of waters were taken in rural communities in South Africa and the Escherichia coli numbers measured. Of the E. coli positive samples, 46% (n = 148) were screened for the presence of E. coli pathogen gene markers. Though synoptic, the survey provided many insights into the issues that drove the study. Container use markedly degraded water quality as judged by indicator counts, even where improved water supply services were in place. Household container use also appeared to promote regrowth or contamination of containers with pathogenic E. coli strains. Polymerase chain reaction (PCR) analysis also showed that the diversity of potential pathogenic E. coli carrying virulence genes was great. All seven genes screened for (Ial, Stx1, Stx2, EaeA, Eagg, ST, LT) were found in the waters, alone or as mixtures (number of different combinations = 31) including those characteristic of the more dangerous invasive and haemorrhagic E. coli strains. Given the central role of containers in the management of water supply to rural communities, it is clear the microbiology of these waters requires much further characterization.

  18. A structural view of the dissociation of Escherichia coli tryptophanase.

    Science.gov (United States)

    Green, Keren; Qasim, Nasrin; Gdaelvsky, Garik; Kogan, Anna; Goldgur, Yehuda; Parola, Abraham H; Lotan, Ofra; Almog, Orna

    2015-12-01

    Tryptophanase (Trpase) is a pyridoxal 5'-phosphate (PLP)-dependent homotetrameric enzyme which catalyzes the degradation of L-tryptophan. Trpase is also known for its cold lability, which is a reversible loss of activity at low temperature (2°C) that is associated with the dissociation of the tetramer. Escherichia coli Trpase dissociates into dimers, while Proteus vulgaris Trpase dissociates into monomers. As such, this enzyme is an appropriate model to study the protein-protein interactions and quaternary structure of proteins. The aim of the present study was to understand the differences in the mode of dissociation between the E. coli and P. vulgaris Trpases. In particular, the effect of mutations along the molecular axes of homotetrameric Trpase on its dissociation was studied. To answer this question, two groups of mutants of the E. coli enzyme were created to resemble the amino-acid sequence of P. vulgaris Trpase. In one group, residues 15 and 59 that are located along the molecular axis R (also termed the noncatalytic axis) were mutated. The second group included a mutation at position 298, located along the molecular axis Q (also termed the catalytic axis). Replacing amino-acid residues along the R axis resulted in dissociation of the tetramers into monomers, similar to the P. vulgaris Trpase, while replacing amino-acid residues along the Q axis resulted in dissociation into dimers only. The crystal structure of the V59M mutant of E. coli Trpase was also determined in its apo form and was found to be similar to that of the wild type. This study suggests that in E. coli Trpase hydrophobic interactions along the R axis hold the two monomers together more strongly, preventing the dissociation of the dimers into monomers. Mutation of position 298 along the Q axis to a charged residue resulted in tetramers that are less susceptible to dissociation. Thus, the results indicate that dissociation of E. coli Trpase into dimers occurs along the molecular Q axis.

  19. Deactivation of Escherichia coli by the plasma needle

    Energy Technology Data Exchange (ETDEWEB)

    Sladek, R E J; Stoffels, E [Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2005-06-07

    In this paper we present a parameter study on deactivation of Escherichia coli (E. coli) by means of a non-thermal plasma (plasma needle). The plasma needle is a small-sized (1 mm) atmospheric glow sustained by radio-frequency excitation. This plasma will be used to disinfect heat-sensitive objects; one of the intended applications is in vivo deactivation of dental bacteria: destruction of plaque and treatment of caries. We use E. coli films plated on agar dishes as a model system to optimize the conditions for bacterial destruction. Plasma power, treatment time and needle-to-sample distance are varied. Plasma treatment of E. coli films results in formation of a bacteria-free void with a size up to 12 mm. 10{sup 4}-10{sup 5} colony forming units are already destroyed after 10 s of treatment. Prolongation of treatment time and usage of high powers do not significantly improve the destruction efficiency: short exposure at low plasma power is sufficient. Furthermore, we study the effects of temperature increase on the survival of E. coli and compare it with thermal effects of the plasma. The population of E. coli heated in a warm water bath starts to decrease at temperatures above 40 deg. C. Sample temperature during plasma treatment has been monitored. The temperature can reach up to 60 deg. C at high plasma powers and short needle-to-sample distances. However, thermal effects cannot account for bacterial destruction at low power conditions. For safe and efficient in vivo disinfection, the sample temperature should be kept low. Thus, plasma power and treatment time should not exceed 150 mW and 60 s, respectively.

  20. Accumulation and efflux of polychlorinated biphenyls in Escherichia coli.

    Science.gov (United States)

    Geng, Shen; Fang, Jun; Turner, Kendrick B; Daunert, Sylvia; Wei, Yinan

    2012-06-01

    Polychlorinated biphenyls (PCBs) are environmental pollutants that have been associated with numerous adverse health effects in human and animals. Hydroxylated PCBs (HPCBs) are the product of the oxidative metabolism of PCBs. The presence of hydroxyl groups in HPCBs makes these compounds more hydrophilic than the parent PCBs. One of the best approaches to break down and remove these contaminants is bioremediation; an environmentally friendly process that uses microorganisms to degrade hazardous chemicals into non-toxic ones. In this study, we investigated the cellular accumulation and toxicity of selected PCBs and HPCBs in Gram-negative bacteria, using Escherichia coli as a model organism. We found that none of the five PCBs tested were toxic to E. coli, presumably due to their limited bioavailability. Nevertheless, different HPCBs tested showed different levels of toxicity. Furthermore, we demonstrated that the primary multidrug efflux system in E. coli, AcrAB-TolC, facilitated the efflux of HPCBs out of the cell. Since AcrAB-TolC is constitutively expressed in E. coli and is conserved in all sequenced Gram-negative bacterial genomes, our results suggest that the efflux activities of multidrug resistant pumps may affect the accumulation and degradation of PCBs in Gram-negative bacteria.

  1. Modification of Artificial Oliogosaccharides in Recombinant Escherichia coli Cells

    Directory of Open Access Journals (Sweden)

    Tomohisa Kato

    2008-01-01

    Full Text Available Artificial oligosaccharides were modified using recombinant Escherichia coli cells that overexpress sialidase. Based on the principle of the saccharide primer method by using bacterial cells overexpressing enzymes related to oligosaccharide modification. Problem statement: It is very hard to obtain oligosaccharides, because they have complex and diverse structures with different linkage patterns and monosaccharide components. Approach: It has been known that various oligosaccharides can be synthesized in mammalian cells from saccharide primers. We attempted to modify oligosaccharides by using bacterial cells overexpressing enzymes related to oligosaccharide modification instead of mammalian cells. Results: The glycosphingolipid-like derivative GM3 was absorbed by the cell and desialylated by the expressed sialidase and the desialylated product was then secreted into the medium. The GM3-type oligosaccharides were not detected from the cell fraction of recombinant E. coli cells that overexpress sialidase differently from recombinant E. coli carrying only vector DNA (pET-19b. Conclusion/Recommendations: E. coli as well as mammalian cells may be used as a biocatalyst for oligosaccharide modification and production of artificial functional oligosaccharides.

  2. Curli fimbria: an Escherichia coli adhesin associated with human cystitis

    Directory of Open Access Journals (Sweden)

    Melina Aparecida Cordeiro

    2016-06-01

    Full Text Available Abstract Escherichia coli is the major causative agent of human cystitis. In this study, a preliminary molecular analysis carried out by PCR (polymerase chain reaction demonstrated that 100% of 31 E. coli strains isolated from patients with recurrent UTIs (urinary tract infections showed the presence of the curli fimbria gene (csgA. Curli fimbria is known to be associated with bacterial biofilm formation but not with the adhesion of human cystitis-associated E. coli. Therefore, this work aimed to study how curli fimbria is associated with uropathogenic E. coli (UPEC as an adhesion factor. For this purpose, the csgA gene was deleted from strain UPEC-4, which carries three adhesion factor genes (csgA, fimH and ompA. The wild-type UPEC-4 strain and its mutant (ΔcsgA were analyzed for their adhesion ability over HTB-9 (human bladder carcinoma, Vero (kidney cells of African green monkey and HUVEC (human umbilical vein cells in the presence of α-D-mannose. All the wild-type UPEC strains tested (100% were able to adhere to all three cell types, while the UPEC-4 ΔcsgA mutant lost its adherence to HTB-9 but continued to adhere to the HUVEC and Vero cells. The results suggest that curli fimbria has an important role in the adhesion processes associated with human UPEC-induced cystitis.

  3. Insights into the biology of Escherichia coli through structural proteomics.

    Science.gov (United States)

    Matte, Allan; Jia, Zongchao; Sunita, S; Sivaraman, J; Cygler, Miroslaw

    2007-09-01

    Escherichia coli has historically been an important organism for understanding a multitude of biological processes, and represents a model system as we attempt to simulate the workings of living cells. Many E. coli strains are also important human and animal pathogens for which new therapeutic strategies are required. For both reasons, a more complete and comprehensive understanding of the protein structure complement of E. coli is needed at the genome level. Here, we provide examples of insights into the mechanism and function of bacterial proteins that we have gained through the Bacterial Structural Genomics Initiative (BSGI), focused on medium-throughput structure determination of proteins from E. coli. We describe the structural characterization of several enzymes from the histidine biosynthetic pathway, the structures of three pseudouridine synthases, enzymes that synthesize one of the most abundant modified bases in RNA, as well as the combined use of protein structure and focused functional analysis to decipher functions for hypothetical proteins. Together, these results illustrate the power of structural genomics to contribute to a deeper biological understanding of bacterial processes.

  4. Redefining the requisite lipopolysaccharide structure in Escherichia coli.

    Science.gov (United States)

    Meredith, Timothy C; Aggarwal, Parag; Mamat, Uwe; Lindner, Buko; Woodard, Ronald W

    2006-02-17

    Gram-negative bacteria possess an asymmetric lipid bilayer surrounding the cell wall, the outer membrane (OM). The OM inner leaflet is primarily composed of various glycerophospholipids, whereas the outer leaflet predominantly contains the unique amphiphilic macromolecule, lipopolysaccharide (LPS or endotoxin). The majority of all gram-negative bacteria elaborate LPS containing at least one 2-keto 3-deoxy-D-manno-octulosonate (Kdo) molecule. The minimal LPS structure required for growth of Escherichia coli has long been recognized as two Kdo residues attached to lipid A, inextricably linking viability to toxicity. Here we report the construction and characterization of the nonconditional E. coli K-12 suppressor strain KPM22 that lacks Kdo and is viable despite predominantly elaborating the endotoxically inactive LPS precursor lipid IV(A). Our results challenge the established E. coli Kdo2-lipid A dogma, indicating that the previously observed and well-documented dependence of cell viability on the synthesis of Kdo stems from a lethal pleiotropy precipitated after the depletion of the carbohydrate, rather than an inherent need for the Kdo molecule itself as an indispensable structural component of the OM LPS layer. Inclusion of the inner membrane LPS transporter MsbA on a multicopy plasmid partially suppresses the lethal deltaKdo phenotype directly in the auxotrophic parent strain, suggesting increased rates of nonglycosylated lipid A transport can, in part, compensate for Kdo depletion. The unprecedented nature of a lipid IV(A) OM redefines the requisite LPS structure for viability in E. coli.

  5. Curli fimbria: an Escherichia coli adhesin associated with human cystitis.

    Science.gov (United States)

    Cordeiro, Melina Aparecida; Werle, Catierine Hirsch; Milanez, Guilherme Paier; Yano, Tomomasa

    2016-01-01

    Escherichia coli is the major causative agent of human cystitis. In this study, a preliminary molecular analysis carried out by PCR (polymerase chain reaction) demonstrated that 100% of 31 E. coli strains isolated from patients with recurrent UTIs (urinary tract infections) showed the presence of the curli fimbria gene (csgA). Curli fimbria is known to be associated with bacterial biofilm formation but not with the adhesion of human cystitis-associated E. coli. Therefore, this work aimed to study how curli fimbria is associated with uropathogenic E. coli (UPEC) as an adhesion factor. For this purpose, the csgA gene was deleted from strain UPEC-4, which carries three adhesion factor genes (csgA, fimH and ompA). The wild-type UPEC-4 strain and its mutant (ΔcsgA) were analyzed for their adhesion ability over HTB-9 (human bladder carcinoma), Vero (kidney cells of African green monkey) and HUVEC (human umbilical vein) cells in the presence of α-d-mannose. All the wild-type UPEC strains tested (100%) were able to adhere to all three cell types, while the UPEC-4 ΔcsgA mutant lost its adherence to HTB-9 but continued to adhere to the HUVEC and Vero cells. The results suggest that curli fimbria has an important role in the adhesion processes associated with human UPEC-induced cystitis.

  6. Magnetically-Actuated Escherichia coli System for Micro Lithography

    Science.gov (United States)

    Lauback, S.; Brown, E.; Pérez-Guzman, L.; Peace, C.; Pierce, C.; Lower, B. H.; Lower, S. K.; Sooryakumar, R.

    2015-03-01

    Technologies that control matter at the nano- and micro-scale are crucial for developing new engineered materials and devices. While the more traditional approaches for such manipulations often depend on lithographic fabrication, they can be expanded upon by taking advantage of the biological systems within a living cell which also operate on the nano- and micro- scale. In this study, a system is being developed to functionalize a targeted location on the surface of a chip with the protein AmCyan from transformed Escherichia coli cells. Using established methods in molecular biology where a plasmid with the amcyan gene sequence is inserted into the cell, E. coli are engineered to express the AmCyan protein on their outer surface. In order to transport the cells to the targeted location, the transformed E. coli are labeled with superparamagnetic micro-beads which exert directed forces on the cells in an external field. Preliminary results of the protein expression on E. coli, the transport of the cell through weak magnetic fields to targeted locations and the potential to transfer protein from the cell to the chip surface will be presented.

  7. Combinatorial biosynthesis of flavones and flavonols in Escherichia coli.

    Science.gov (United States)

    Miyahisa, Ikuo; Funa, Nobutaka; Ohnishi, Yasuo; Martens, Stefan; Moriguchi, Takaya; Horinouchi, Sueharu

    2006-06-01

    (2S)-Flavanones (naringenin and pinocembrin) are key intermediates in the flavonoid biosynthetic pathway in plants. Recombinant Escherichia coli cells containing four genes for a phenylalanine ammonia-lyase, cinnamate/coumarate:CoA ligase, chalcone synthase, and chalcone isomerase, in addition to the acetyl-CoA carboxylase, have been established for efficient production of (2S)-naringenin from tyrosine and (2S)-pinocembrin from phenylalanine. Further introduction of the flavone synthase I gene from Petroselinum crispum under the control of the T7 promoter and the synthetic ribosome-binding sequence in pACYCDuet-1 caused the E. coli cells to produce flavones: apigenin (13 mg/l) from tyrosine and chrysin (9.4 mg/l) from phenylalanine. Introduction into the E. coli cells of the flavanone 3beta-hydroxylase and flavonol synthase genes from the plant Citrus species led to production of flavonols: kaempferol (15.1 mg/l) from tyrosine and galangin (1.1 mg/l) from phenylalanine. The combinatorial biosynthesis of the flavones and flavonols in E. coli is promising for the construction of a library of various flavonoid compounds and un-natural flavonoids in bacteria.

  8. Genomic analysis of extra-intestinal pathogenic Escherichia coli urosepsis.

    Science.gov (United States)

    McNally, A; Alhashash, F; Collins, M; Alqasim, A; Paszckiewicz, K; Weston, V; Diggle, M

    2013-08-01

    Urosepsis is a bacteraemia infection caused by an organism previously causing an infection in the urinary tract of a patient, a diagnosis which has been classically confirmed by culture of the same species of bacteria from both blood and urine samples. Given the new insights afforded by sequencing technologies into the complicated population structures of infectious agents affecting humans, we sought to investigate urosepsis by comparing the genome sequences of blood and urine isolates of Escherichia coli from five patients with urosepsis. The results confirm the classical urosepsis hypothesis in four of the five cases, but also show the complex nature of extra-intestinal E. coli infection in the fifth case, where three distinct strains caused two distinct infections. Additionally, we show there is little to no variation in the bacterial genome as it progressed from urine to blood, and also present a minimal set of virulence genes required for bacteraemia in E. coli based on gene association. These suggest that most E. coli have the genetic propensity to cause bacteraemia.

  9. [Investigation of pathogenic Escherichia coli strains in patients with diarrhea].

    Science.gov (United States)

    Aydın Tutak, Gülten; Tuğrul, Hamdi Murat

    2015-01-01

    The role of certain serogroups and serotypes of Escherichia coli in the etiology of gastroenteritis is increasingly appreciated. It is important to detect the virulence factors of diarrheagenic E.coli strains that differentiate them from nonpathogenic members of normal intestinal flora for the diagnosis and treatment. The aims of this study were to determine the serotypes of E.coli isolates that cause gastroenteritis and to investigate the presence of virulence genes by polymerase chain reaction (PCR). A total of 202 watery, bloody or mucoid stool samples sent to microbiology laboratory collected from patients with diarrhea who were admitted to outpatient clinics of Trakya University Health Research and Application Hospital between February to October 2009, were included in the study. A total of 254 predominantly grown E.coli strains have been isolated and identified with conventional methods from the cultures of those 202 samples. All strains were tested by slide agglutination (SA) that includes 6 units of O serogroups polyvalent antisera of enteropathogenic E.coli (EPEC), enterotoxigenic E.coli (ETEC) and enteroinvasive E.coli (EIEC). The samples which yielded positive results with SA test and the same number of negative samples selected with mapping method as controls were studied for the presence of virulence genes belonging EPEC, ETEC and EIEC by conventional PCR. In the study, 14.3% (29/202) of the samples were serogrouped with SA, of them 13 (6.4%) were identified as EPEC, 11 (5.4%) as EIEC and five (2.4%) as ETEC. Only five isolates belonging to EPEC serogroup could be defined by monovalent antiserum and they were all in O1 serogroup. Out of 29 pathogenic E.coli serotyped, 3 (10.3%) of them harbored the virulence genes of diarrheagenic strains. One sample which was positive for eaeA gene of EPEC, did not harbor bfpA and stx genes and was defined as atypical EPEC. Out of other two samples, one was positive for estA gene of ETEC and the other one for ial gene

  10. Prevalence of Antibiotic Resistance in Escherichia coli Isolated from Poultry Meat Supply in Isfahan

    Directory of Open Access Journals (Sweden)

    Farhad Safarpordehkordi

    2014-08-01

    Conclusions: Despite the high contamination rate of chicken meat with Escherichia coli, majority of isolates had high resistance to common antibiotics. Complete cooking of meat and avoid indiscriminate prescribing of antibiotics, preventing the occurrence of food poisoning due to resistant Escherichia coli.

  11. High-level quinolone resistance is associated with the overexpression of smeVWX in Stenotrophomonas maltophilia clinical isolates.

    Science.gov (United States)

    García-León, G; Ruiz de Alegría Puig, C; García de la Fuente, C; Martínez-Martínez, L; Martínez, J L; Sánchez, M B

    2015-05-01

    Stenotrophomonas maltophilia is the only known bacterium in which quinolone-resistant isolates do not present mutations in the genes encoding bacterial topoisomerases. The expression of the intrinsic quinolone resistance elements smeDEF, smeVWX and Smqnr was analysed in 31 clinical S. maltophilia isolates presenting a minimum inhibitory concentration (MIC) range to ciprofloxacin between 0.5 and > 32 μg/mL; 11 (35.5%) overexpressed smeDEF, 2 (6.5%) presenting the highest quinolone MICs overexpressed smeVWX and 1 (3.2%) overexpressed Smqnr. Both strains overexpressing smeVWX presented changes at the Gly266 position of SmeRv, the repressor of smeVWX. Changes at the same position were previously observed in in vitro selected S. maltophilia quinolone-resistant mutants, indicating this amino acid is highly relevant for the activity of SmeRv in repressing smeVWX expression. For the first time SmeVWX overexpression is associated with quinolone resistance of S. maltophilia clinical isolates.

  12. Atypical Enteropathogenic Escherichia coli Secretes Plasmid Encoded Toxin

    Directory of Open Access Journals (Sweden)

    Rita C. Ruiz

    2014-01-01

    Full Text Available Plasmid encoded toxin (Pet is a serine protease originally described in enteroaggregative Escherichia coli (EAEC prototype strain 042 whose entire characterization was essentially obtained from studies performed with the purified toxin. Here we show that Pet is not exclusive to EAEC. Atypical enteropathogenic Escherichia coli (aEPEC strains, isolated from diarrhea cases, express Pet and its detection in supernatants of infected HEp-2 cells coincides with the appearance of cell damage, which, in turn, were similar to those described with purified Pet. Pet secretion and the cytotoxic effects are time and culture medium dependent. In presence of DMEM supplemented with tryptone cell rounding and detachment were observed after just 5 h of incubation with the bacteria. In the absence of tryptone, the cytotoxic effects were detected only after 24 h of infection. We also show that, in addition to the prototype EAEC, other pet+ EAEC strains, also isolated from diarrhea cases, induce cellular damage in the same degree as the aEPEC. The cytotoxic effects of EAEC and aEPEC strains were significantly reduced in the presence of a serine protease inhibitor or anti-Pet IgG serum. Our results show a common aspect between the aEPEC and EAEC and provide the first evidence pointing to a role of Pet in aEPEC pathogenesis.

  13. Localization of the Tat translocon components in Escherichia coli.

    Science.gov (United States)

    Berthelmann, Felix; Brüser, Thomas

    2004-07-02

    The Tat system has the ability to translocate folded proteins across the bacterial cytoplasmic membrane. In Escherichia coli, three functionally different translocon components have been identified, namely TatA, TatB, and TatC. These proteins were fused to the green fluorescent protein (GFP) and their localization was determined by confocal laser scanning fluorescence microscopy. TatA-GFP was distributed in the membrane, often with higher abundance at the poles. TatB-GFP was found in distinct spots at the poles of the cells. The fluorescence of TatC-GFP was very low and required a constitutive expression system to become higher than background, but then appearing polar. All three constructs complemented the chain-formation phenotype of corresponding mutant strains, indicating the functionality of the fusion proteins. TatB-GFP and TatC-GFP also complemented TMAO respiration deficiency and TatA-GFP the SDS-sensitivity of the mutant strains. The localization of the translocon-GFP fusions coincides with the fluorescence pattern of GFP fusions to Tat substrate signal sequences. We suggest that the active translocon complexes are mainly present at polar positions in Escherichia coli.

  14. Kinetics of Schiff base on Escherichia coli by microcalorimetry

    Institute of Scientific and Technical Information of China (English)

    许名飞; 李新海; 万洪文; 刘义

    2003-01-01

    The influence of four kinds of Schiff bases on a strain of Escherichia coli was studied by microcalorimetry. Differences in their capabilities of suppressing the metabolism of this bacterium were observed. The results show that the extent and duration of the inhibitory effect on the metabolism as judged from the multiplication rate constant, k, varies with different Schiff bases.The multiplication rate constant k, of Escherichia coli (in log phase) in the presence of Mo-salicylioaldehyde-thiadizole, Mo-piperonaldehyde-thiosemicarbazone and Mo-3-methoxy-salicylicaldehyde-thiadizole decreases with the increase of concentrations of compounds c, and the relationships between k and c, maximum heat production rate Pm and c, peak time of growth curves tp and c are of linearity. For Mo-6-nitro-pieronalde-thiosemicarbazone, the multiplication rate constant is constant irrespective of variation in concentration. The sequence of antibiotic activity of Schiff base is: Mo-salicylioaldehyde-thiadizole>Mo-3-methoxy-salicylicaldehyde-thiadizole>Mo-piperonaldehyde-thiosemicarbazone> 6-nitro-pieronalde-thiosemicarbazone.

  15. Brote causado por Escherichia coli en Chalco, México

    Directory of Open Access Journals (Sweden)

    Cortés-Ortiz Iliana Alejandra

    2002-01-01

    Full Text Available Objetivo. Identificar el agente causal del brote de diarrea asociado con el desbordamiento del canal de aguas negras en Chalco. Material y métodos. Estudio retrospectivo y transversal, efectuado en el Instituto de Diagnóstico y Referencia Epidemiológicos (InDRE, de la Secretaría de Salud, con 1 550 hisopos rectales para el aislamiento e identificación bioquímica de V. cholerae y enterobacterias, obtenidos de la población del Valle de Chalco, que presentó diarrea y vómito durante el desastre natural acontecido el 31 de mayo de 2000. El análisis de los resultados se efectuó por la diferencia entre las proporciones de dos poblaciones (prueba de Ji cuadrada. Las cepas de E. coli se hibridaron por "colony blot" para los grupos ETEC, EIEC, EPEC y EHEC. Resultados. El 0.45% correspondió a Salmonella: S. agona, S. infantis, S. enteritidis, S. muenchen, S. typhimurium; 0.06% a Shigella flexneri 3a, y 76.6% a E. coli: 62.2% a ETEC (44.6 % con LT, 11.2% con ST, y 44.1% con ambas sondas, 0.84% a EIEC (sonda ial, 0.84% a EPEC (sonda bundle-forming pilus BFP, 0.08% a E. coli enterohemorrágica no-O157:H7 (sonda pCVD419, y 36.02% no hibridó. No se encontró asociación entre E. coli patógena con la edad y género. Conclusiones. Escherichia coli podría ser responsable del brote de diarrea. Es importante conocer el agente etiológico del brote para encaminar las estrategias en el estudio y control sanitario del mismo.

  16. A Novel Putrescine Exporter SapBCDF of Escherichia coli.

    Science.gov (United States)

    Sugiyama, Yuta; Nakamura, Atsuo; Matsumoto, Mitsuharu; Kanbe, Ayaka; Sakanaka, Mikiyasu; Higashi, Kyohei; Igarashi, Kazuei; Katayama, Takane; Suzuki, Hideyuki; Kurihara, Shin

    2016-12-16

    Recent research has suggested that polyamines (putrescine, spermidine, and spermine) in the intestinal tract impact the health of animals either negatively or positively. The concentration of polyamines in the intestinal tract results from the balance of uptake and export of the intestinal bacteria. However, the mechanism of polyamine export from bacterial cells to the intestinal lumen is still unclear. In Escherichia coli, PotE was previously identified as a transporter responsible for putrescine excretion in an acidic growth environment. We observed putrescine concentration in the culture supernatant was increased from 0 to 50 μm during growth of E. coli under neutral conditions. Screening for the unidentified putrescine exporter was performed using a gene knock-out collection of E. coli, and deletion of sapBCDF significantly decreased putrescine levels in the culture supernatant. Complementation of the deletion mutant with the sapBCDF genes restored putrescine levels in the culture supernatant. Additionally, the ΔsapBCDF strain did not facilitate uptake of putrescine from the culture supernatant. Quantification of stable isotope-labeled putrescine derived from stable isotope-labeled arginine supplemented in the medium revealed that SapBCDF exported putrescine from E. coli cells to the culture supernatant. It was previously reported that SapABCDF of Salmonella enterica sv. typhimurium and Haemophilus influenzae conferred resistance toantimicrobial peptides; however, the E. coli ΔsapBCDF strain did not affect resistance to antimicrobial peptide LL-37. These results strongly suggest that the natural function of the SapBCDF proteins is the export of putrescine.

  17. Discovery of Escherichia coli CRISPR sequences in an undergraduate laboratory.

    Science.gov (United States)

    Militello, Kevin T; Lazatin, Justine C

    2017-05-01

    Clustered regularly interspaced short palindromic repeats (CRISPRs) represent a novel type of adaptive immune system found in eubacteria and archaebacteria. CRISPRs have recently generated a lot of attention due to their unique ability to catalog foreign nucleic acids, their ability to destroy foreign nucleic acids in a mechanism that shares some similarity to RNA interference, and the ability to utilize reconstituted CRISPR systems for genome editing in numerous organisms. In order to introduce CRISPR biology into an undergraduate upper-level laboratory, a five-week set of exercises was designed to allow students to examine the CRISPR status of uncharacterized Escherichia coli strains and to allow the discovery of new repeats and spacers. Students started the project by isolating genomic DNA from E. coli and amplifying the iap CRISPR locus using the polymerase chain reaction (PCR). The PCR products were analyzed by Sanger DNA sequencing, and the sequences were examined for the presence of CRISPR repeat sequences. The regions between the repeats, the spacers, were extracted and analyzed with BLASTN searches. Overall, CRISPR loci were sequenced from several previously uncharacterized E. coli strains and one E. coli K-12 strain. Sanger DNA sequencing resulted in the discovery of 36 spacer sequences and their corresponding surrounding repeat sequences. Five of the spacers were homologous to foreign (non-E. coli) DNA. Assessment of the laboratory indicates that improvements were made in the ability of students to answer questions relating to the structure and function of CRISPRs. Future directions of the laboratory are presented and discussed. © 2016 by The International Union of Biochemistry and Molecular Biology, 45(3):262-269, 2017. © 2016 The International Union of Biochemistry and Molecular Biology.

  18. Evaluation of the efficacy of an autogenous Escherichia coli vaccine in broiler breeders

    DEFF Research Database (Denmark)

    Li, Lili; Thøfner, Ida; Christensen, Jens Peter

    2017-01-01

    In poultry production Escherichia coli autogenous vaccines are often used. However, the efficacy of autogenous E. coli vaccinations has not been evaluated experimentally in chickens after start of lay. The aim of the present study was to evaluate the protective effect of an autogenous E. coli...... infection, significant protection of an autogenous E. coli vaccine against neither a homologous nor a heterologous E. coli challenge could not be documented....

  19. The Impact of Antibiotic Stewardship Programs in Combating Quinolone Resistance: A Systematic Review and Recommendations for More Efficient Interventions.

    Science.gov (United States)

    Pitiriga, Vasiliki; Vrioni, Georgia; Saroglou, George; Tsakris, Athanasios

    2017-04-01

    Quinolones are among the most commonly prescribed antibiotics worldwide. A clear relationship has been demonstrated between excessive quinolone use and the steady increase in the incidence of quinolone-resistant bacterial pathogens, both in hospital and community sites. In addition, exposure to quinolones has been associated with colonization and infection with healthcare-associated pathogens such as methicillin-resistant Staphylococcus aureus and Clostridium difficile in hospitalized patients. Therefore, the management of quinolone prescribing in hospitals through antibiotic stewardship programs is considered crucial. Although suggestions have been made by previous studies on the positive impact of stewardship programs concerning the emergence and spread of multidrug-resistant bacteria at hospital level, the association of quinolone-targeted interventions with reduction of quinolone resistance is vague. The purpose of this article was to evaluate the impact of stewardship interventions on quinolone resistance rates and healthcare-associated infections, through a literature review using systematic methods to identify and select the appropriate studies. Recommendations for improvements in quinolone-targeted stewardship programs are also proposed. Efforts in battling quinolone resistance should combine various interventions such as restriction formulary policies, prospective audits with feedback to prescribers, infection prevention and control measures, prompt detection of low-level resistance, educational programs, and guidelines for optimal quinolone usage. However, the effectiveness of such strategies should be assessed by properly designed and conducted clinical trials. Finally, novel approaches in diagnostic stewardship for rapidly detecting bacterial resistance, including PCR-based techniques, mass spectrometry, microarrays, and whole-genome sequencing as well as the prompt investigation on the clonality of quinolone-resistant strains, will strengthen our

  20. Immobilizing live Escherichia coli for AFM studies of surface dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Lonergan, N.E.; Britt, L.D.; Sullivan, C.J., E-mail: sullivcj@evms.edu

    2014-02-01

    Atomic force microscopy (AFM) is a probe-based technique that permits high resolution imaging of live bacterial cells. However, stably immobilizing cells to withstand the probe-based lateral forces remains an obstacle in AFM mediated studies, especially those of live, rod shaped bacteria in nutrient media. Consequently, AFM has been under-utilized in the research of bacterial surface dynamics. The aim of the current study was to immobilize a less adherent Escherichia coli strain in a method that both facilitates AFM imaging in nutrient broth and preserves overall cell viability. Immobilization reagents and buffers were systematically evaluated and the cell membrane integrity was monitored in all sample preparations. As expected, the biocompatible gelatin coated surfaces facilitated stable cell attachment in lower ionic strength buffers, yet poorly immobilized cells in higher ionic strength buffers. In comparison, poly-L-lysine surfaces bound cells in both low and high ionic strength buffers. The benefit of the poly-L-lysine binding capacity was offset by the compromised membrane integrity exhibited by cells on poly-L-lysine surfaces. However, the addition of divalent cations and glucose to the immobilization buffer was found to mitigate this unfavorable effect. Ultimately, immobilization of E. coli cells on poly-L-lysine surfaces in a lower ionic strength buffer supplemented with Mg{sup 2+} and Ca{sup 2+} was determined to provide optimal cell attachment without compromising the overall cell viability. Cells immobilized in this method were stably imaged in media through multiple division cycles. Furthermore, permeability assays indicated that E. coli cells recover from the hypoosmotic stress caused by immobilization in low ionic strength buffers. Taken together, this data suggests that stable immobilization of viable cells on poly-L-lysine surfaces can be accomplished in lower ionic strength buffers that are supplemented with divalent cations for membrane

  1. Escherichia coli Meningitis after Rotavirus Gastroenteritis in an Infant

    Science.gov (United States)

    Vermezoglu, Oznur; Ocal Topcu, Didem; Karbuz, Adem; Hacihamdioglu, Bulent

    2016-01-01

    Although rotavirus gastroenteritis is quite common in the pediatric population, secondary bacterial sepsis following rotavirus infection is a rare clinical entity. Gram-negative bacilli are the fifth most common cause of meningitis in infants but this infection rarely occurs after gastroenteritis. Here, we report a 2.5-month-old infant who developed Escherichia coli (E. coli) meningitis after acute rotavirus gastroenteritis. The 2.5-month-old male infant with fever, vomiting, and watery diarrhea that started 1 day earlier was admitted to the hospital. Rotavirus antigen in stool sample was positive. He was hospitalized, and fever was measured at 39.5°C on the second day. Lumbar puncture was done for suspicion of meningitis, and cerebrospinal fluid (CSF) findings suggested meningitis. Intravenous vancomycin and cefotaxime were started empirically. Since E. coli reproduction was seen in blood culture and CSF culture, treatment was continued with cefotaxime. The patient was discharged with minimal midlevel hydrocephalus findings in cranial ultrasonography and magnetic resonance imaging following 21 days of antibiotics treatment. Septicemia development following rotavirus gastroenteritis is an extremely rare clinical condition. It is vital to start prompt antibiotic treatment as soon as the diagnosis of secondary bacterial infection is made because of high mortality and morbidity rates.

  2. Identification of diarrheagenic Escherichia coli strains from avian organic fertilizers.

    Science.gov (United States)

    Puño-Sarmiento, Juan; Gazal, Luis Eduardo; Medeiros, Leonardo P; Nishio, Erick K; Kobayashi, Renata K T; Nakazato, Gerson

    2014-08-28

    The Brazilian poultry industry generates large amounts of organic waste, such as chicken litter, which is often used in agriculture. Among the bacteria present in organic fertilizer are members of the Enterobacteriaceae family. The objective of this study was to detect the presence of diarrheagenic Escherichia coli (DEC) strains in avian organic fertilizer, and assess the potential damage they can cause in humans due to antimicrobial resistance. The presence of DEC pathotypes and phylogenetic groups were detected by multiplex-PCR. Phenotypic assays, such as tests for adhesion, cytotoxicity activity, biofilm formation and especially antimicrobial susceptibility, were performed. Fifteen DEC strains from 64 E. coli were isolated. Among these, four strains were classified as enteropathogenic (EPEC; 6.2%), three strains as Shiga toxin-producing (STEC; 4.7%), 10 strains as enteroaggregative (EAEC; 12.5%), but two of these harbored the eaeA gene too. The low number of isolated strains was most likely due to the composting process, which reduces the number of microorganisms. These strains were able to adhere to HEp-2 and HeLa cells and produce Shiga-toxins and biofilms; in addition, some of the strains showed antimicrobial resistance, which indicates a risk of the transfer of resistance genes to human E. coli. These results showed that DEC strains isolated from avian organic fertilizers can cause human infections.

  3. Metabolic engineering of Escherichia coli for the production of xylonate.

    Directory of Open Access Journals (Sweden)

    Yujin Cao

    Full Text Available Xylonate is a valuable chemical for versatile applications. Although the chemical synthesis route and microbial conversion pathway were established decades ago, no commercial production of xylonate has been obtained so far. In this study, the industrially important microorganism Escherichia coli was engineered to produce xylonate from xylose. Through the coexpression of a xylose dehydrogenase (xdh and a xylonolactonase (xylC from Caulobacter crescentus, the recombinant strain could convert 1 g/L xylose to 0.84 g/L xylonate and 0.10 g/L xylonolactone after being induced for 12 h. Furthermore, the competitive pathway for xylose catabolism in E. coli was blocked by disrupting two genes (xylA and xylB encoding xylose isomerase and xylulose kinase. Under fed-batch conditions, the finally engineered strain produced up to 27.3 g/L xylonate and 1.7 g/L xylonolactone from 30 g/L xylose, about 88% of the theoretical yield. These results suggest that the engineered E. coli strain has a promising perspective for large-scale production of xylonate.

  4. Improving alkane synthesis in Escherichia coli via metabolic engineering.

    Science.gov (United States)

    Song, Xuejiao; Yu, Haiying; Zhu, Kun

    2016-01-01

    Concerns about energy security and global petroleum supply have made the production of renewable biofuels an industrial imperative. The ideal biofuels are n-alkanes in that they are chemically and structurally identical to the fossil fuels and can "drop in" to the transportation infrastructure. In this work, an Escherichia coli strain that produces n-alkanes was constructed by heterologous expression of acyl-acyl carrier protein (ACP) reductase (AAR) and aldehyde deformylating oxygenase (ADO) from Synechococcus elongatus PCC7942. The accumulation of alkanes ranged from 3.1 to 24.0 mg/L using different expressing strategies. Deletion of yqhD, an inherent aldehyde reductase in E. coli, or overexpression of fadR, an activator for fatty acid biosynthesis, exhibited a nearly twofold increase in alkane titers, respectively. Combining yqhD deletion and fadR overexpression resulted in a production titer of 255.6 mg/L in E. coli, and heptadecene was the most abundant product.

  5. Escherichia coli lipoprotein binds human plasminogen via an intramolecular domain

    Directory of Open Access Journals (Sweden)

    Tammy eGonzalez

    2015-10-01

    Full Text Available Escherichia coli lipoprotein (Lpp is a major cellular component that exists in two distinct states, bound-form and free-form. Bound-form Lpp is known to interact with the periplasmic bacterial cell wall, while free-form Lpp is localized to the bacterial cell surface. A function for surface-exposed Lpp has yet to be determined. We hypothesized that the presence of C-terminal lysines in the surface-exposed region of Lpp would facilitate binding to the host zymogen plasminogen, a protease commandeered by a number of clinically important bacteria. Recombinant Lpp was synthesized and the binding of Lpp to plasminogen, the effect of various inhibitors on this binding, and the effects of various mutations of Lpp on Lpp-plasminogen interactions were examined. Additionally, the ability of Lpp-bound plasminogen to be converted to active plasmin was analyzed. We determined that Lpp binds plasminogen via an atypical domain located near the center of mature Lpp that may not be exposed on the surface of intact E. coli according to the current localization model. Finally, we found that plasminogen bound by Lpp can be converted to active plasmin. While the consequences of Lpp binding plasminogen are unclear, these results prompt further investigation of the ability of surface exposed Lpp to interact with host molecules such as extracellular matrix components and complement regulators, and the role of these interactions in infections caused by E. coli and other bacteria.

  6. Recombinant expression of Streptococcus pneumoniae capsular polysaccharides in Escherichia coli.

    Science.gov (United States)

    Kay, Emily J; Yates, Laura E; Terra, Vanessa S; Cuccui, Jon; Wren, Brendan W

    2016-04-01

    Currently, Streptococcus pneumoniae is responsible for over 14 million cases of pneumonia worldwide annually, and over 1 million deaths, the majority of them children. The major determinant for pathogenesis is a polysaccharide capsule that is variable and is used to distinguish strains based on their serotype. The capsule forms the basis of the pneumococcal polysaccharide vaccine (PPV23) that contains purified capsular polysaccharide from 23 serotypes, and the pneumococcal conjugate vaccine (PCV13), containing 13 common serotypes conjugated to CRM197 (mutant diphtheria toxin). Purified capsule from S. pneumoniae is required for pneumococcal conjugate vaccine production, and costs can be prohibitively high, limiting accessibility of the vaccine in low-income countries. In this study, we demonstrate the recombinant expression of the capsule-encoding locus from four different serotypes of S. pneumoniae within Escherichia coli. Furthermore, we attempt to identify the minimum set of genes necessary to reliably and efficiently express these capsules heterologously. These E. coli strains could be used to produce a supply of S. pneumoniae serotype-specific capsules without the need to culture pathogenic bacteria. Additionally, these strains could be applied to synthetic glycobiological applications: recombinant vaccine production using E. coli outer membrane vesicles or coupling to proteins using protein glycan coupling technology.

  7. Characterization of pyruvate uptake in Escherichia coli K-12.

    Directory of Open Access Journals (Sweden)

    Jens Kreth

    Full Text Available The monocarboxylate pyruvate is an important metabolite and can serve as sole carbon source for Escherichia coli. Although specific pyruvate transporters have been identified in two bacterial species, pyruvate transport is not well understood in E. coli. In the present study, pyruvate transport was investigated under different growth conditions. The transport of pyruvate shows specific activities depending on the growth substrate used as sole carbon source, suggesting the existence of at least two systems for pyruvate uptake: i one inducible system and probably highly specific for pyruvate and ii one system active under non-induced conditions. Using the toxic pyruvate analog 3-fluoropyruvate, a mutant was isolated unable to grow on and transport pyruvate. Further investigation revealed that a revertant selected for growth on pyruvate regained the inducible pyruvate transport activity. Characterization of pyruvate excretion showed that the pyruvate transport negative mutant accumulated pyruvate in the growth medium suggesting an additional transport system for pyruvate excretion. The here presented data give valuable insight into the pyruvate metabolism and transport of E. coli suggesting the presence of at least two uptake systems and one excretion system to balance the intracellular level of pyruvate.

  8. Thermal impulse response and the temperature preference of Escherichia coli

    Science.gov (United States)

    Ryu, William

    2010-03-01

    From a broad perspective, exposure to environmental temperature changes is a universal condition of living organisms. Escherichia coli is a powerful model system to study how a biochemical network measures and processes thermal information to produce adaptive changes in behavior. E. coli performs thermotaxis, directing its movements to a preferred temperature in spatial thermal gradients. How does the system perform thermotaxis? Where biologically is this analog value of thermal preference stored? Previous studies using populations of cells have shown that E.coli accumulate in spatial thermal gradients, but these experiments did not cleanly separate thermal responses from chemotactic responses. Here we have isolated the thermal behavior by studying the thermal impulse response of single, tethered cells. The motor output of cells was measured in response to small, impulsive increases in temperature, delivered by an infrared laser, over a range of ambient temperature (23 to 43 degrees C). The thermal impulse response at temperatures 31 degrees C, some cells show an inverted response, switching from warm- to cold-seeking behavior. The fraction of inverted responses increases nonlinearly with temperature, switching steeply at the preferred temperature of 37 degrees C.

  9. Global functional atlas of Escherichia coli encompassing previously uncharacterized proteins.

    Directory of Open Access Journals (Sweden)

    Pingzhao Hu

    2009-04-01

    Full Text Available One-third of the 4,225 protein-coding genes of Escherichia coli K-12 remain functionally unannotated (orphans. Many map to distant clades such as Archaea, suggesting involvement in basic prokaryotic traits, whereas others appear restricted to E. coli, including pathogenic strains. To elucidate the orphans' biological roles, we performed an extensive proteomic survey using affinity-tagged E. coli strains and generated comprehensive genomic context inferences to derive a high-confidence compendium for virtually the entire proteome consisting of 5,993 putative physical interactions and 74,776 putative functional associations, most of which are novel. Clustering of the respective probabilistic networks revealed putative orphan membership in discrete multiprotein complexes and functional modules together with annotated gene products, whereas a machine-learning strategy based on network integration implicated the orphans in specific biological processes. We provide additional experimental evidence supporting orphan participation in protein synthesis, amino acid metabolism, biofilm formation, motility, and assembly of the bacterial cell envelope. This resource provides a "systems-wide" functional blueprint of a model microbe, with insights into the biological and evolutionary significance of previously uncharacterized proteins.

  10. Identification of Diarrheagenic Escherichia coli Strains from Avian Organic Fertilizers

    Directory of Open Access Journals (Sweden)

    Juan Puño-Sarmiento

    2014-08-01

    Full Text Available The Brazilian poultry industry generates large amounts of organic waste, such as chicken litter, which is often used in agriculture. Among the bacteria present in organic fertilizer are members of the Enterobacteriaceae family. The objective of this study was to detect the presence of diarrheagenic Escherichia coli (DEC strains in avian organic fertilizer, and assess the potential damage they can cause in humans due to antimicrobial resistance. The presence of DEC pathotypes and phylogenetic groups were detected by multiplex-PCR. Phenotypic assays, such as tests for adhesion, cytotoxicity activity, biofilm formation and especially antimicrobial susceptibility, were performed. Fifteen DEC strains from 64 E. coli were isolated. Among these, four strains were classified as enteropathogenic (EPEC; 6.2%, three strains as Shiga toxin-producing (STEC; 4.7%, 10 strains as enteroaggregative (EAEC; 12.5%, but two of these harbored the eaeA gene too. The low number of isolated strains was most likely due to the composting process, which reduces the number of microorganisms. These strains were able to adhere to HEp-2 and HeLa cells and produce Shiga-toxins and biofilms; in addition, some of the strains showed antimicrobial resistance, which indicates a risk of the transfer of resistance genes to human E. coli. These results showed that DEC strains isolated from avian organic fertilizers can cause human infections.

  11. Escherichia coli bacteria detection by using graphene-based biosensor.

    Science.gov (United States)

    Akbari, Elnaz; Buntat, Zolkafle; Afroozeh, Abdolkarim; Zeinalinezhad, Alireza; Nikoukar, Ali

    2015-10-01

    Graphene is an allotrope of carbon with two-dimensional (2D) monolayer honeycombs. A larger detection area and higher sensitivity can be provided by graphene-based nanosenor because of its 2D structure. In addition, owing to its special characteristics, including electrical, optical and physical properties, graphene is known as a more suitable candidate compared to other materials used in the sensor application. A novel model employing a field-effect transistor structure using graphene is proposed and the current-voltage (I-V) characteristics of graphene are employed to model the sensing mechanism. This biosensor can detect Escherichia coli (E. coli) bacteria, providing high levels of sensitivity. It is observed that the graphene device experiences a drastic increase in conductance when exposed to E. coli bacteria at 0-10(5) cfu/ml concentration. The simple, fast response and high sensitivity of this nanoelectronic biosensor make it a suitable device in screening and functional studies of antibacterial drugs and an ideal high-throughput platform which can detect any pathogenic bacteria. Artificial neural network and support vector regression algorithms have also been used to provide other models for the I-V characteristic. A satisfactory agreement has been presented by comparison between the proposed models with the experimental data.

  12. Rotational tumbling of Escherichia coli aggregates under shear

    Science.gov (United States)

    Portela, R.; Patrício, P.; Almeida, P. L.; Sobral, R. G.; Franco, J. M.; Leal, C. R.

    2016-12-01

    Growing living cultures of Escherichia coli bacteria are investigated using real-time in situ rheology and rheoimaging measurements. In the early stages of growth (lag phase) and when subjected to a constant stationary shear, the viscosity slowly increases with the cell's population. As the bacteria reach the exponential phase of growth, the viscosity increases rapidly, with sudden and temporary abrupt decreases and recoveries. At a certain stage, corresponding grossly to the late phase of growth, when the population stabilizes, the viscosity also keeps its maximum constant value, with drops and recoveries, for a long period of time. This complex rheological behavior, which is observed to be shear strain dependent, is a consequence of two coupled effects: the cell density continuous increase and its changing interacting properties. Particular attention is given to the late phase of growth of E. coli populations under shear. Rheoimaging measurements reveal, near the static plate, a rotational motion of E. coli aggregates, collectively tumbling and flowing in the shear direction. This behavior is interpreted in the light of a simple theoretical approach based on simple rigid body mechanics.

  13. Adenosine diphosphate sugar pyrophosphatase prevents glycogen biosynthesis in Escherichia coli

    Science.gov (United States)

    Moreno-Bruna, Beatriz; Baroja-Fernández, Edurne; Muñoz, Francisco José; Bastarrica-Berasategui, Ainara; Zandueta-Criado, Aitor; Rodríguez-López, Milagros; Lasa, Iñigo; Akazawa, Takashi; Pozueta-Romero, Javier

    2001-01-01

    An adenosine diphosphate sugar pyrophosphatase (ASPPase, EC 3.6.1.21) has been characterized by using Escherichia coli. This enzyme, whose activities in the cell are inversely correlated with the intracellular glycogen content and the glucose concentration in the culture medium, hydrolyzes ADP-glucose, the precursor molecule of glycogen biosynthesis. ASPPase was purified to apparent homogeneity (over 3,000-fold), and sequence analyses revealed that it is a member of the ubiquitously distributed group of nucleotide pyrophosphatases designated as “nudix” hydrolases. Insertional mutagenesis experiments leading to the inactivation of the ASPPase encoding gene, aspP, produced cells with marginally low enzymatic activities and higher glycogen content than wild-type bacteria. aspP was cloned into an expression vector and introduced into E. coli. Transformed cells were shown to contain a dramatically reduced amount of glycogen, as compared with the untransformed bacteria. No pleiotropic changes in the bacterial growth occurred in both the aspP-overexpressing and aspP-deficient strains. The overall results pinpoint the reaction catalyzed by ASPPase as a potential step of regulating glycogen biosynthesis in E. coli. PMID:11416161

  14. Escherichia coli Meningitis after Rotavirus Gastroenteritis in an Infant

    Directory of Open Access Journals (Sweden)

    Gamze Ozgurhan

    2016-01-01

    Full Text Available Although rotavirus gastroenteritis is quite common in the pediatric population, secondary bacterial sepsis following rotavirus infection is a rare clinical entity. Gram-negative bacilli are the fifth most common cause of meningitis in infants but this infection rarely occurs after gastroenteritis. Here, we report a 2.5-month-old infant who developed Escherichia coli (E. coli meningitis after acute rotavirus gastroenteritis. The 2.5-month-old male infant with fever, vomiting, and watery diarrhea that started 1 day earlier was admitted to the hospital. Rotavirus antigen in stool sample was positive. He was hospitalized, and fever was measured at 39.5°C on the second day. Lumbar puncture was done for suspicion of meningitis, and cerebrospinal fluid (CSF findings suggested meningitis. Intravenous vancomycin and cefotaxime were started empirically. Since E. coli reproduction was seen in blood culture and CSF culture, treatment was continued with cefotaxime. The patient was discharged with minimal midlevel hydrocephalus findings in cranial ultrasonography and magnetic resonance imaging following 21 days of antibiotics treatment. Septicemia development following rotavirus gastroenteritis is an extremely rare clinical condition. It is vital to start prompt antibiotic treatment as soon as the diagnosis of secondary bacterial infection is made because of high mortality and morbidity rates.

  15. Escherichia coli Chromosomal Loci Segregate from Midcell with Universal Dynamics.

    Science.gov (United States)

    Cass, Julie A; Kuwada, Nathan J; Traxler, Beth; Wiggins, Paul A

    2016-06-21

    The structure of the Escherichia coli chromosome is inherently dynamic over the duration of the cell cycle. Genetic loci undergo both stochastic motion around their initial positions and directed motion to opposite poles of the rod-shaped cell during segregation. We developed a quantitative method to characterize cell-cycle dynamics of the E. coli chromosome to probe the chromosomal steady-state mobility and segregation process. By tracking fluorescently labeled chromosomal loci in thousands of cells throughout the entire cell cycle, our method allows for the statistical analysis of locus position and motion, the step-size distribution for movement during segregation, and the locus drift velocity. The robust statistics of our detailed analysis of the wild-type E. coli nucleoid allow us to observe loci moving toward midcell before segregation occurs, consistent with a replication factory model. Then, as segregation initiates, we perform a detailed characterization of the average segregation velocity of loci. Contrary to origin-centric models of segregation, which predict distinct dynamics for oriC-proximal versus oriC-distal loci, we find that the dynamics of loci were universal and independent of genetic position.

  16. Colibri: a functional data base for the Escherichia coli genome.

    Science.gov (United States)

    Médigue, C; Viari, A; Hénaut, A; Danchin, A

    1993-09-01

    Several data libraries have been created to organize all the data obtained worldwide about the Escherichia coli genome. Because the known data now amount to more than 40% of the whole genome sequence, it has become necessary to organize the data in such a way that appropriate procedures can associate knowledge produced by experiments about each gene to its position on the chromosome and its relation to other relevant genes, for example. In addition, global properties of genes, affected by the introduction of new entries, should be present as appropriate description fields. A data base, implemented on Macintosh by using the data base management system 4th Dimension, is described. It is constructed around a core constituted by known contigs of E. coli sequences and links data collected in general libraries (unmodified) to data associated with evolving knowledge (with modifiable fields). Biologically significant results obtained through the coupling of appropriate procedures (learning or statistical data analysis) are presented. The data base is available through a 4th Dimension runtime and through FTP on Internet. It has been regularly updated and will be systematically linked to other E. coli data bases (M. Kroger, R. Wahl, G. Schachtel, and P. Rice, Nucleic Acids Res. 20(Suppl.):2119-2144, 1992; K. E. Rudd, W. Miller, C. Werner, J. Ostell, C. Tolstoshev, and S. G. Satterfield, Nucleic Acids Res. 19:637-647, 1991) in the near future.

  17. Characterization of the YdeO regulon in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Yuki Yamanaka

    Full Text Available Enterobacteria are able to survive under stressful conditions within animals, such as acidic conditions in the stomach, bile salts during transfer to the intestine and anaerobic conditions within the intestine. The glutamate-dependent (GAD system plays a major role in acid resistance in Escherichia coli, and expression of the GAD system is controlled by the regulatory cascade consisting of EvgAS > YdeO > GadE. To understand the YdeO regulon in vivo, we used ChIP-chip to interrogate the E. coli genome for candidate YdeO binding sites. All of the seven operons identified by ChIP-chip as being potentially regulated by YdeO were confirmed as being under the direct control of YdeO using RT-qPCR, EMSA, DNaseI-footprinting and reporter assays. Within this YdeO regulon, we identified four stress-response transcription factors, DctR, NhaR, GadE, and GadW and enzymes for anaerobic respiration. Both GadE and GadW are involved in regulation of the GAD system and NhaR is an activator for the sodium/proton antiporter gene. In conjunction with co-transcribed Slp, DctR is involved in protection against metabolic endoproducts under acidic conditions. Taken all together, we suggest that YdeO is a key regulator of E. coli survival in both acidic and anaerobic conditions.

  18. Characterization of the YdeO regulon in Escherichia coli.

    Science.gov (United States)

    Yamanaka, Yuki; Oshima, Taku; Ishihama, Akira; Yamamoto, Kaneyoshi

    2014-01-01

    Enterobacteria are able to survive under stressful conditions within animals, such as acidic conditions in the stomach, bile salts during transfer to the intestine and anaerobic conditions within the intestine. The glutamate-dependent (GAD) system plays a major role in acid resistance in Escherichia coli, and expression of the GAD system is controlled by the regulatory cascade consisting of EvgAS > YdeO > GadE. To understand the YdeO regulon in vivo, we used ChIP-chip to interrogate the E. coli genome for candidate YdeO binding sites. All of the seven operons identified by ChIP-chip as being potentially regulated by YdeO were confirmed as being under the direct control of YdeO using RT-qPCR, EMSA, DNaseI-footprinting and reporter assays. Within this YdeO regulon, we identified four stress-response transcription factors, DctR, NhaR, GadE, and GadW and enzymes for anaerobic respiration. Both GadE and GadW are involved in regulation of the GAD system and NhaR is an activator for the sodium/proton antiporter gene. In conjunction with co-transcribed Slp, DctR is involved in protection against metabolic endoproducts under acidic conditions. Taken all together, we suggest that YdeO is a key regulator of E. coli survival in both acidic and anaerobic conditions.

  19. Plasmid-mediated quinolone resistance; interactions between human, animal and environmental ecologies

    Directory of Open Access Journals (Sweden)

    Laurent ePOIREL

    2012-02-01

    Full Text Available Resistance to quinolones and fluoroquinolones is being increasingly reported among human but also veterinary isolates during the last two to three decades, very likely as a consequence of the large clinical usage of those antibiotics. Even if the principle mechanisms of resistance to quinolones are chromosome-encoded, due to modifications of molecular targets (DNA gyrase and topoisomerase IV, decreased outer-membrane permeability (porin defect and overexpression of naturally-occurring efflux, the emergence of plasmid-mediated quinolone resistance (PMQR has been reported since 1998. Although these PMQR determinants confer low-level resistance to quinolones and/or fluoroquinolones, they are a favorable background for selection of additional chromosome-encoded quinolone resistance mechanisms. Different transferable mechanisms have been identified, corresponding to the production of Qnr proteins, of the aminoglycoside acetyltransferase AAC(6’-Ib-cr, or of the QepA-type or OqxAB-type efflux pumps. Qnr proteins protect target enzymes (DNA gyrase and type IV topoisomerase from quinolone inhibition (mostly nalidixic acid. The AAC(6’-Ib-cr determinant acetylates several fluoroquinolones, such as norfloxacin and ciprofloxacin. Finally, the QepA and OqxAB efflux pumps extrude fluoroquinolones from the bacterial cell. A series of studies have identified the environment to be a reservoir of PMQR genes, with farm animals and aquatic habitats being significantly involved. In addition, the origin of the qnr genes has been identified, corresponding to the waterborne species Shewanella sp. Altogether, the recent observations suggest that the aquatic environment might constitute the original source of PMQR genes, that would secondly spread among animal or human isolates.

  20. Multiple Antimicrobial Resistance of Escherichia coli Isolated from Chickens in Iran

    OpenAIRE

    Reza Talebiyan; Mehdi Kheradmand; Faham Khamesipour; Mohammad Rabiee-Faradonbeh

    2014-01-01

    Antimicrobial agents are used extremely in order to reduce the great losses caused by Escherichia coli infections in poultry industry. In this study, 318 pathogenic Escherichia coli (APEC) strains isolated from commercial broiler flocks with coli-septicemia were examined for antimicrobials of both veterinary and human significance by disc diffusion method. Multiple resistances to antimicrobial agents were observed in all the isolates. Resistance to the antibiotics was as follows: Tylosin (88....

  1. Extraintestinal pathogenic Escherichia coli are associated with intestinal inflammation in patients with ulcerative colitis

    DEFF Research Database (Denmark)

    Mirsepasi-Lauridsen, Hengameh C; Halkjaer, Sofie Ingdam; Mortensen, Esben Munk;

    2016-01-01

    E. coli of the phylogenetic group B2 harbouring Extra intestinal Pathogenic Escherichia coli (ExPEC) genes are frequently seen as colonizers of the intestine in patients with active ulcerative colitis (UC). In this study, we describe the influence of E. coli Nissle (EcN) B2 as add-on treatment to...... scores in comparison to patients colonized with E. coli A and D (p treatment of UC patients with E. coli Nissle (B2) does not promote clinical remission and active UC patients colonized with E. coli B2 have an increased intestinal inflammation.......E. coli of the phylogenetic group B2 harbouring Extra intestinal Pathogenic Escherichia coli (ExPEC) genes are frequently seen as colonizers of the intestine in patients with active ulcerative colitis (UC). In this study, we describe the influence of E. coli Nissle (EcN) B2 as add-on treatment...

  2. Starved Escherichia coli preserve reducing power under nitric oxide stress

    Energy Technology Data Exchange (ETDEWEB)

    Gowers, Glen-Oliver F. [Department of Molecular Biology, Princeton University, Princeton, NJ (United States); Robinson, Jonathan L. [Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ (United States); Brynildsen, Mark P., E-mail: mbrynild@princeton.edu [Department of Molecular Biology, Princeton University, Princeton, NJ (United States); Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ (United States)

    2016-07-15

    Nitric oxide (NO) detoxification enzymes, such as NO dioxygenase (NOD) and NO reductase (NOR), are important to the virulence of numerous bacteria. Pathogens use these defense systems to ward off immune-generated NO, and they do so in environments that contain additional stressors, such as reactive oxygen species, nutrient deprivation, and acid stress. NOD and NOR both use reducing equivalents to metabolically deactivate NO, which suggests that nutrient deprivation could negatively impact their functionality. To explore the relationship between NO detoxification and nutrient deprivation, we examined the ability of Escherichia coli to detoxify NO under different levels of carbon source availability in aerobic cultures. We observed failure of NO detoxification under both carbon source limitation and starvation, and those failures could have arisen from inabilities to synthesize Hmp (NOD of E. coli) and/or supply it with sufficient NADH (preferred electron donor). We found that when limited quantities of carbon source were provided, NO detoxification failed due to insufficient NADH, whereas starvation prevented Hmp synthesis, which enabled cells to maintain their NADH levels. This maintenance of NADH levels under starvation was confirmed to be dependent on the absence of Hmp. Intriguingly, these data show that under NO stress, carbon-starved E. coli are better positioned with regard to reducing power to cope with other stresses than cells that had consumed an exhaustible amount of carbon. -- Highlights: •Carbon source availability is critical to aerobic E. coli NO detoxification. •Carbon source starvation, under NO stress, preserves intracellular NADH levels. •Preservation of NADH depends on starvation-dependent inhibition of Hmp induction.

  3. Kinetic modelling of central carbon metabolism in Escherichia coli.

    Science.gov (United States)

    Peskov, Kirill; Mogilevskaya, Ekaterina; Demin, Oleg

    2012-09-01

    In the present study, we developed a detailed kinetic model of Escherichia coli central carbon metabolism. The main model assumptions were based on the results of metabolic and regulatory reconstruction of the system and thorough model verification with experimental data. The development and verification of the model included several stages, which allowed us to take into account both in vitro and in vivo experimental data and avoid the ambiguity that frequently occurs in detailed models of biochemical pathways. The choice of the level of detail for the mathematical description of enzymatic reaction rates and the evaluation of parameter values were based on available published data. Validation of the complete model of the metabolic pathway describing specific physiological states was based on fluxomics and metabolomics data. In particular, we developed a model that describes aerobic growth of E. coli in continuous culture with a limiting concentration of glucose. Such modification of the model was used to integrate experimental metabolomics data obtained in steady-state conditions for wild-type E. coli and genetically modified strains, e.g. knockout of the pyruvate kinase gene (pykA). Following analysis of the model behaviour, and comparison of the coincidence between predicted and experimental data, it was possible to investigate the functional and regulatory properties of E. coli central carbon metabolism. For example, a novel metabolic regulatory mechanism for 6-phosphogluconate dehydrogenase inhibition by phosphoenolpyruvate was hypothesized, and the flux ratios between the reactions catalysed by enzyme isoforms were predicted. The mathematical model described here has been submitted to the JWS Online Cellular Systems Modelling Database and can be accessed at http://jjj.biochem.sun.ac.za/database/peskov/index.html © 2012 The Authors Journal compilation © 2012 FEBS.

  4. An end-joining repair mechanism in Escherichia coli

    Science.gov (United States)

    Chayot, Romain; Montagne, Benjamin; Mazel, Didier; Ricchetti, Miria

    2010-01-01

    Bridging broken DNA ends via nonhomologous end-joining (NHEJ) contributes to the evolution and stability of eukaryote genomes. Although some bacteria possess a simplified NHEJ mechanism, the human commensal Escherichia coli is thought to rely exclusively on homology-directed mechanisms to repair DNA double-strand breaks (DSBs). We show here that laboratory and pathogenic E. coli strains possess a distinct end-joining activity that repairs DSBs and generates genome rearrangements. This mechanism, named alternative end-joining (A-EJ), does not rely on the key NHEJ proteins Ku and Ligase-D which are absent in E. coli. Differently from classical NHEJ, A-EJ is characterized by extensive end-resection largely due to RecBCD, by overwhelming usage of microhomology and extremely rare DNA synthesis. We also show that A-EJ is dependent on the essential Ligase-A and independent on Ligase-B. Importantly, mutagenic repair requires a functional Ligase-A. Although generally mutagenic, accurate A-EJ also occurs and is frequent in some pathogenic bacteria. Furthermore, we show the acquisition of an antibiotic-resistance gene via A-EJ, refuting the notion that bacteria gain exogenous sequences only by recombination-dependent mechanisms. This finding demonstrates that E. coli can integrate unrelated, nonhomologous exogenous sequences by end-joining and it provides an alternative strategy for horizontal gene transfer in the bacterial genome. Thus, A-EJ contributes to bacterial genome evolution and adaptation to environmental challenges. Interestingly, the key features of A-EJ also appear in A-NHEJ, an alternative end-joining mechanism implicated in chromosomal translocations associated with human malignancies, and we propose that this mutagenic repair might have originated in bacteria. PMID:20133858

  5. Engineering an Escherichia coli platform to synthesize designer biodiesels.

    Science.gov (United States)

    Wierzbicki, Michael; Niraula, Narayan; Yarrabothula, Akshitha; Layton, Donovan S; Trinh, Cong T

    2016-04-20

    Biodiesels, fatty acid esters (FAEs), can be synthesized by condensation of fatty acid acyl CoAs and alcohols via a wax ester synthase in living cells. Biodiesels have advantageous characteristics over petrodiesels such as biodegradability, a higher flash point, and less emission. Controlling fatty acid and alcohol moieties are critical to produce designer biodiesels with desirable physiochemical properties (e.g., high cetane number, low kinematic viscosity, high oxidative stability, and low cloud point). Here, we developed a flexible framework to engineer Escherichia coli cell factories to synthesize designer biodiesels directly from fermentable sugars. In this framework, we designed each FAE pathway as a biodiesel exchangeable production module consisting of acyl CoA, alcohol, and wax ester synthase submodules. By inserting the FAE modules in an engineered E. coli modular chassis cell, we generated E. coli cell factories to produce targeted biodiesels (e.g., fatty acid ethyl (FAEE) and isobutyl (FAIbE) esters) with tunable and controllable short-chain alcohol moieties. The engineered E. coli chassis carrying the FAIbE production module produced 54mg/L FAIbEs with high specificity, accounting for>90% of the total synthesized FAEs and ∼4.7 fold increase in FAIbE production compared to the wildtype. Fed-batch cultures further improved FAIbE production up to 165mg/L. By mixing ethanol and isobutanol submodules, we demonstrated controllable production of mixed FAEEs and FAIbEs. We envision the developed framework offers a flexible, alternative route to engineer designer biodiesels with tunable and controllable properties using biomass-derived fermentable sugars. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. The location of the restriction locus for λ·K in Escherichia coli B

    NARCIS (Netherlands)

    Hoekstra, W.P.M.; Haan, P.G. de

    1965-01-01

    Analysis of recombinants from E. coli K 12 Hfr × E. coli B F− crosses showed that one locus on the chromosome of Escherichia coli, controlling restriction and probably also the modification of phage λ, is located between the leading point of the Hfr H chromosome and the locus for threonine synthesis

  7. Construction and shuttling of novel bifunctional vectors for Streptomyces spp. and Escherichia coli.

    OpenAIRE

    Neesen, K; Volckaert, G.

    1989-01-01

    Shuttle vectors for gene transfer between Streptomyces spp. and Escherichia coli have been constructed by fusion of an artificial multicopy E. coli replicon and DNA fragments of pIJ702. Stable transfer to Streptomyces lividans was obtained. Marked differences in transformation efficiency were observed when plasmid DNA isolated from E. coli GM119 was used instead of that from strain HB101.

  8. Mechanisms of antibiotic resistance to enrofloxacin in uropathogenic Escherichia coli in dog

    Science.gov (United States)

    Escherichia coli (E. coli) urinary tract infections (UTIs) are becoming a serious problem both for pets and humans (zoonosis) due to the close contact and to the increasing resistance to antibiotics. Canine E. coli represents a good experimental model useful to study this pathology. Moreover, as des...

  9. Risk factors for ESBL-producing Escherichia coli on pig farms

    NARCIS (Netherlands)

    Dohmen, Wietske; Dorado-García, Alejandro; Bonten, Marc J.M.; Wagenaar, Jaap A.; Mevius, Dik; Heederik, Dick J.J.

    2017-01-01

    The presence of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-E. coli) in food animals is a public health concern. This study aimed to determine prevalence of ESBL-E. coli on pig farms and to assess the effect of reducing veterinary antimicrobial use (AMU) and farm management

  10. DIARRHEA, UROSEPSIS AND HEMOLYTIC UREMIC SYNDROME CAUSED BY THE SAME HETEROPATHOGENIC ESCHERICHIA COLI STRAIN

    NARCIS (Netherlands)

    Ang, C. Wim; Bouts, Antonia H. M.; Rossen, John W. A.; Van der Kuip, Martijn; Van Heerde, Marc; Bokenkamp, Arend

    2016-01-01

    We describe an 8-month-old girl with diarrhea, urosepsis and hemolytic uremic syndrome caused by Escherichia coli. Typing of cultured E. coli strains from urine and blood revealed the presence of virulence factors from multiple pathotypes of E. coli. This case exemplifies the genome plasticity of E.

  11. Proteomic differences between Escherichia coli strains that cause transient versus persistent intramammary infections [abstract

    Science.gov (United States)

    Escherichia coli is a leading cause of bacterial mastitis in dairy cattle. Typically this infection is transient in nature and lasts 2-3 days. However, in a minority of cases, E. coli can cause a persistent intramammary infection. The mechanisms that enable certain strains of E. coli to cause a p...

  12. Detection of Escherichia Coli O157:H7 in Fecal Samples in Meat Goats

    Science.gov (United States)

    Mobley, Ray; Madden, Uford; Brooks-Walter, Alexis

    2004-01-01

    Studies have reported the isolation of Escherichia coli (E. coli)O157:H7 from pork, lamb and poultry products, and from other animals including deer, horses, dogs, birds and humans. There is limited or no information on the presence of the organism in goats. The objectives of this study were to determine if E. coli O157:H7 was naturally occurring…

  13. A rare presentation of ischemic pseudomembranous colitis due to Escherichia coli O157:H7.

    Science.gov (United States)

    Kendrick, Jessica B; Risbano, Michael; Groshong, Steve D; Frankel, Stephen K

    2007-07-15

    Escherichia coli Ol57:H7 infection ranges from mild diarrheal illness to severe hemorrhagic colitis but may rarely be complicated by pseudomembranous colitis and/or necrosis. Herein, we report a sporadic case of ischemic E. coli Ol57:H7 pseudomembranous colitis in an adult that occurred during a national outbreak of E. coli Ol57:H7 in the United States.

  14. Complete genome sequences of Escherichia coli strains 1303 and ECC-1470 isolated from bovine mastitis

    NARCIS (Netherlands)

    Leimbach, Andreas; Poehlein, Anja; Witten, Anika; Scheutz, Flemming; Schukken, Ynte; Daniel, Rolf; Dobrindt, Ulrich

    2016-01-01

    Escherichia coli is the leading causative agent of acute bovine mastitis. Here, we report the complete genome sequence of E. coli O70:H32 strain 1303, isolated from an acute case of bovine mastitis, and E. coli Ont:Hnt strain ECC-1470, isolated from a persistent infection.

  15. Characterization of pathogenic Escherichia coli isolated from humans in Austria : phenotypes, toxin gene types and epidemiology

    NARCIS (Netherlands)

    Wagner, M; Allerberger, F; Manafi, M; Lindner, G; Friedrich, A W; Sonntag, A-K; Foissy, H

    2004-01-01

    One hundred and ten clinical Escherichia coli isolates of serovar O157 (n = 102) and O26 (n = 8) were characterized for the presence of putative virulence genes by PCR. All but one of these isolates contained the eae gene. The EHEC-hly gene could be detected in all E. coli O157 and in 50% of E. coli

  16. Attaching and effacing Escherichia coli isolates from Danish children: clinical significance and microbiological characteristics

    DEFF Research Database (Denmark)

    Jensen, C; Ethelberg, S; Olesen, B

    2007-01-01

    This study describes the prevalence, clinical manifestations and microbiological characteristics of attaching and effacing Escherichia coli isolates, i.e., enteropathogenic E. coli (EPEC) belonging to the classical EPEC serotypes, non-EPEC attaching and effacing E. coli (A/EEC) and verocytotoxin...

  17. Characterization of pathogenic Escherichia coli isolated from humans in Austria : phenotypes, toxin gene types and epidemiology

    NARCIS (Netherlands)

    Wagner, M; Allerberger, F; Manafi, M; Lindner, G; Friedrich, A W; Sonntag, A-K; Foissy, H

    2004-01-01

    One hundred and ten clinical Escherichia coli isolates of serovar O157 (n = 102) and O26 (n = 8) were characterized for the presence of putative virulence genes by PCR. All but one of these isolates contained the eae gene. The EHEC-hly gene could be detected in all E. coli O157 and in 50% of E. coli

  18. IncA/C plasmid-mediated spread of CMY-2 in multidrug-resistant Escherichia coli from food animals in China.

    Science.gov (United States)

    Guo, Yu-Fang; Zhang, Wen-Hui; Ren, Si-Qi; Yang, Lin; Lü, Dian-Hong; Zeng, Zhen-Ling; Liu, Ya-Hong; Jiang, Hong-Xia

    2014-01-01

    To obtain a broad molecular epidemiological characterization of plasmid-mediated AmpC β-lactamase CMY-2 in Escherichia coli isolates from food animals in China. A total of 1083 E. coli isolates from feces, viscera, blood, drinking water, and sub-surface soil were examined for the presence of CMY-2 β-lactamases. CMY-2-producing isolates were characterized as follows: the blaCMY-2 genotype was determined using PCR and sequencing, characterization of the blaCMY-2 genetic environment, plasmid sizing using S1 nuclease pulsed-field gel electrophoresis (PFGE), PCR-based replicon typing, phylogenetic grouping, XbaI-PFGE, and multi-locus sequence typing (MLST). All 31 CMY-2 producers were only detected in feces, and presented with multidrug resistant phenotypes. All CMY-2 strains also co-harbored genes conferring resistance to other antimicrobials, including extended spectrum β-lactamases genes (blaCTX-M-14 or blaCTX-M-55), plasmid-mediated quinolone resistance determinants (qnr, oqxA, and aac-(6')-Ib-cr), floR and rmtB. The co-transferring of blaCMY-2 with qnrS1 and floR (alone and together) was mainly driven by the Inc A/C type plasmid, with sizes of 160 or 200 kb. Gene cassette arrays inserted in the class 1 or class 2 integron were amplified among 12 CMY-2 producers. CMY-2 producers belonged to avirulent groups B1 (n = 12) and A (n = 11), and virulent group D (n = 8). There was a good correlation between phylogenetic groups and sequence types (ST). Twenty-four STs were identified, of which the ST complexes (STC) 101/B1 (n = 6), STC10/A (n = 5), and STC155/B1 (n = 3) were dominant. CMY-2 is the dominant AmpC β-lactamase in food animals and is associated with a transferable replicon IncA/C plasmid in the STC101, STC10, and STC155 strains.

  19. IncA/C plasmid-mediated spread of CMY-2 in multidrug-resistant Escherichia coli from food animals in China.

    Directory of Open Access Journals (Sweden)

    Yu-Fang Guo

    Full Text Available OBJECTIVES: To obtain a broad molecular epidemiological characterization of plasmid-mediated AmpC β-lactamase CMY-2 in Escherichia coli isolates from food animals in China. METHODS: A total of 1083 E. coli isolates from feces, viscera, blood, drinking water, and sub-surface soil were examined for the presence of CMY-2 β-lactamases. CMY-2-producing isolates were characterized as follows: the blaCMY-2 genotype was determined using PCR and sequencing, characterization of the blaCMY-2 genetic environment, plasmid sizing using S1 nuclease pulsed-field gel electrophoresis (PFGE, PCR-based replicon typing, phylogenetic grouping, XbaI-PFGE, and multi-locus sequence typing (MLST. RESULTS: All 31 CMY-2 producers were only detected in feces, and presented with multidrug resistant phenotypes. All CMY-2 strains also co-harbored genes conferring resistance to other antimicrobials, including extended spectrum β-lactamases genes (blaCTX-M-14 or blaCTX-M-55, plasmid-mediated quinolone resistance determinants (qnr, oqxA, and aac-(6'-Ib-cr, floR and rmtB. The co-transferring of blaCMY-2 with qnrS1 and floR (alone and together was mainly driven by the Inc A/C type plasmid, with sizes of 160 or 200 kb. Gene cassette arrays inserted in the class 1 or class 2 integron were amplified among 12 CMY-2 producers. CMY-2 producers belonged to avirulent groups B1 (n = 12 and A (n = 11, and virulent group D (n = 8. There was a good correlation between phylogenetic groups and sequence types (ST. Twenty-four STs were identified, of which the ST complexes (STC 101/B1 (n = 6, STC10/A (n = 5, and STC155/B1 (n = 3 were dominant. CONCLUSIONS: CMY-2 is the dominant AmpC β-lactamase in food animals and is associated with a transferable replicon IncA/C plasmid in the STC101, STC10, and STC155 strains.

  20. The comprehensive updated regulatory network of Escherichia coli K-12

    Directory of Open Access Journals (Sweden)

    Karp Peter D

    2006-01-01

    Full Text Available Abstract Background Escherichia coli is the model organism for which our knowledge of its regulatory network is the most extensive. Over the last few years, our project has been collecting and curating the literature concerning E. coli transcription initiation and operons, providing in both the RegulonDB and EcoCyc databases the largest electronically encoded network available. A paper published recently by Ma et al. (2004 showed several differences in the versions of the network present in these two databases. Discrepancies have been corrected, annotations from this and other groups (Shen-Orr et al., 2002 have been added, making the RegulonDB and EcoCyc databases the largest comprehensive and constantly curated regulatory network of E. coli K-12. Results Several groups have been using these curated data as part of their bioinformatics and systems biology projects, in combination with external data obtained from other sources, thus enlarging the dataset initially obtained from either RegulonDB or EcoCyc of the E. coli K12 regulatory network. We kindly obtained from the groups of Uri Alon and Hong-Wu Ma the interactions they have added to enrich their public versions of the E. coli regulatory network. These were used to search for original references and curate them with the same standards we use regularly, adding in several cases the original references (instead of reviews or missing references, as well as adding the corresponding experimental evidence codes. We also corrected all discrepancies in the two databases available as explained below. Conclusion One hundred and fifty new interactions have been added to our databases as a result of this specific curation effort, in addition to those added as a result of our continuous curation work. RegulonDB gene names are now based on those of EcoCyc to avoid confusion due to gene names and synonyms, and the public releases of RegulonDB and EcoCyc are henceforth synchronized to avoid confusion due to